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TMH 3

Specifications for the Provision

of Traffic and Weigh-in-Motion

Monitoring Services

Vers ion 1 .3

Nov 2015

Commit tee of Transpor t Of f ic ia ls

COTOSouth Africa

Committee of Transport

Officials

COTOSouth Africa

Committee of Transport

Officials

TECHNICAL METHODS

FOR HIGHWAYS

TMH 3

Specifications for the

Provision of Traffic and Weigh-

in-Motion Monitoring Services

Vers ion 1 .3

Nov 2015

Commit tee of Transpor t Of f ic ia ls

Traffic and Weigh-in-Motion Monitoring Specifications

Specifications for the Provision of Traffic and Weigh-in-Motion Monitoring Services

Compiled under the auspices of the:

Roads Coordinating Body (RCB)

Committee of Transport Officials (COTO)

Published by:

The South African National Roads Agency Limited

PO Box 415, Pretoria, 0001

Disclaimer of Liability

The document is provided “as is” without any warranty of any kind, expressed or implied.

No warranty or representation is made, either expressed or implied, with respect to fitness

of use and no responsibility will be accepted by the Committee or the authors for any losses,

damages or claims of any kind, including, without limitation, direct, indirect, special,

incidental, consequential or any other loss or damages that may arise from the use of the

document.

All rights reserved

No part of this document may be modified or amended without the permission and approval

of the Roads Coordinating Body (RCB). Permission is granted to freely copy, print,

reproduce or distribute this document.



Technical Methods for Highways:

The Technical Methods for Highways consists of a series of publications in which methods

are prescribed for use on various aspects related to highway engineering. The documents

are primarily aimed at ensuring the use of uniform methods throughout South Africa.

Users of the documents must ensure that the latest editions or versions of the document

are used. When a document is referred to in other documents, the reference should be to

the latest edition or version of the document.

Any comments on the document will be welcomed and should be forwarded to the publisher

of the document. When appropriate, such comments may be incorporated in future editions

of the document.

Synopsis:

Traffic and Weigh-in-Motion (WIM) monitoring systems are used for the measurement and

collection of various traffic and vehicle characteristics, such as traffic counts, operating

speeds and axle loads. These characteristics are mainly intended for use in the

management, planning and design of road networks.

Provision is also made for the screening of heavy vehicles at weighbridges but not for law

enforcement. The specifications are not suitable for law enforcement purposes and such

purposes have specifically been excluded from the scope of the specifications.

This document describes a functional specification for Traffic and WIM monitoring systems.

The specifications are aimed at ensuring that such systems are of an acceptable quality

and standard, and that collected data comply with certain requirements.

Withdrawal of previous publication:

This publication replaces the previous Draft TMH3 “Traffic axle load surveys for pavement

design” which was published in 1988. This previous publication is effectively withdrawn with

the publication of this document.



Table of Contents

ITEM PAGE

Definitions i

PARTS OF THE SPECIFICATIONS

Part 1 Certification and quality assurance requirements 5

Part 2 Automatic monitoring system requirements 24

Part 3 Automatic monitoring site and system installation requirements 56

Part 4 Manual traffic monitoring requirements 72

Part 5 Monitoring service and data requirements 88

Part 6 Service specification and payment requirements 102

Part 7 Appendices to the specifications 111

CHAPTERS OF THE SPECIFICATIONS

1 SCOPE OF SPECIFICATIONS 1

1.1 Background 1

1.2 Automatic traffic and WIM monitoring services 1

1.3 Manual traffic monitoring services 2

1.4 SI System of units 2

1.5 Overview of specifications 2

2 SERVICE PROVIDER AND MONITORING SYSTEM CERTIFICATION 7

2.1 Certification requirements 7

2.2 System Suppliers and Service Providers 7

2.3 Certification organisation 8

2.4 Traffic and WIM Monitoring System Certificates 8

2.5 Traffic and WIM Monitoring Service Provider Certification 9

2.6 Traffic and WIM Monitoring Service Provider Assessment 10

2.7 System Supplier and Service Provider Contractual Agreement 11

2.8 Manual Traffic Monitoring Service Provider Certification 11

3 TRAFFIC AND WIM MONITORING SYSTEM SUPPLIER QUALITY ASSURANCE 12

3.1 Quality assurance requirements 12

3.2 System supplier quality assurance measures 12

3.3 Service provider quality assurance measures 14

3.4 Service provider monitoring system manuals 14

3.5 Service provider quality assurance manuals 15

3.6 Service provider training and assessment 16

3.7 Installed monitoring system inspection and assessment 17

4 TRAFFIC AND WIM MONITORING SERVICE PROVIDER QUALITY ASSURANCE 18


4.2 Quality assurance measures 18

4.3 Personnel training and assessment 19

5 MANUAL TRAFFIC MONITORING SERVICE PROVIDER QUALITY ASSURANCE 20


5.2 Quality assurance measures 20



5.3 Quality assurance manuals 21

5.4 Training and assessment 22

6 GENERAL AUTOMATIC MONITORING SYSTEM REQUIREMENTS 26

6.1 General requirements 26

6.2 Environmental conditions 26

6.3 Environmental requirements 26

6.4 Operational requirements 27

6.5 Power provision requirements 27

6.6 Data recording capabilities 27

6.7 Data extraction requirements 28

7 AUTOMATIC TRAFFIC MONITORING SYSTEM REQUIREMENTS 29

7.1 System requirements 29

7.2 Traffic monitoring system type and accuracy specification 29

7.3 Traffic monitoring system size specification 32

7.4 Detection capabilities 32

7.5 Data requirements 33

7.6 Resolution requirements 35

7.7 Detection accuracy 36

7.8 Vehicle categorization (classification) accuracy 37

7.9 Speed, length and axle spacing accuracy 38

8 HS WIM MONITORING SYSTEM REQUIREMENTS 40

8.1 HS WIM requirements 40

8.2 Static and dynamic loads 40

8.3 HS WIM Monitoring system types 40

8.4 HS WIM Monitoring system sizes 41

8.5 Accuracy levels 41

8.6 Detection capabilities 41

8.7 Screening requirements 42


8.9 HS WIM Sensor step requirements 43


8.11 Axle detection and axle spacing accuracy 43

8.12 Load accuracy 43

8.13 Calibration of HS WIM systems 45

9 LS WIM MONITORING SYSTEM REQUIREMENTS 46

9.1 LS WIM requirements 46

9.2 System size specification 46

9.3 Operational requirements 46



9.6 Load accuracy 47

10 AUTOMATIC MONITORING SYSTEM ASSESSMENT 49

10.1 System assessments 49

10.2 Monitoring system assessment reviews 49

10.3 Monitoring system assessment 49

10.4 Monitoring system components 50

10.5 Assessment site 50

10.6 Assessment duration 51



10.7 Evidentiary documentation 51

10.8 Visual inspection assessment 52

10.9 Operational assessment 53

10.10 Accuracy assessment 53

10.11 Data assessment 55

11 AUTOMATIC MONITORING SYSTEM REQUIREMENTS 58

11.1 Site requirements 58

11.2 Monitoring site definition 58

11.3 Monitoring site stratification 58

11.4 Monitoring site location 59

11.5 Existing monitoring sites 59

11.6 Road geometry and pavement requirements 59

11.7 Road geometry requirements 60

11.8 Road pavement requirements 61

11.9 LS WIM Sites 62

11.10 Power provision requirements 63

11.11 Traffic channelling devices 63

11.12 Obstructions and services 63

11.13 Additional considerations 64

11.14 Site information records 64

12 INSTALLED AUTOMATIC MONITORING SYSTEM REQUIREMENTS 65

12.1 Introduction 65

12.2 Installation requirements 65

12.3 Removal requirements 66

13 INSTALLED AUTOMATIC MONITORING SYSTEM ASSESSMENTS 68


13.2 Installed monitoring system assessments 68

13.3 Visual assessment of the installed monitoring system 68

13.4 Monitoring system accuracy assessments 69

13.5 Installed measuring system assessment report 69

13.6 Remedial measures 69

14 SITE WORKS REQUIREMENTS 70


14.2 Wayleave application 70

14.3 Work on properties outside road reserve 70

14.4 Traffic accommodation 71

14.5 Legal requirements 71

15 MANUAL TRAFFIC MONITORING TYPES 74

15.1 Manual traffic monitoring 74

15.2 Manual monitoring types 74

15.3 Type M1 video-based monitoring 75

15.4 Type M2 individual monitoring 76

15.5 Type M3 interval monitoring 76

15.6 Employer quality control measures 78

15.7 Traffic data requirements 80

15.8 Monitoring service interruption Error! Bookmark not defined.

16 MANUAL TRAFFIC MONITORING SITE REQUIREMENTS 82

16.1 Link and intersection monitoring 82



16.2 Link monitoring sites 82

16.3 Intersection monitoring sites 83

16.4 Monitoring site stratification 83

16.5 Site information records 84

17 TRAFFIC MONITOR FIELDWORKER REQUIREMENTS 86

17.1 Traffic monitor fieldworker requirements 86

17.2 Communication facilities 86

17.3 Relief fieldworker 86

17.4 Ablution facilities 87

17.5 Adverse weather conditions Error! Bookmark not defined.

17.6 Road safety 87

18 MONITORING SERVICE REQUIREMENTS 90


18.2 Monitoring service types 90

18.3 Monitoring start dates 90

18.4 Monitoring durations 92

18.5 Monitoring programme 93

18.6 Monthly meetings 94

18.7 Non-performance 95

19 MONITORING DATA REQUIREMENTS 96


19.2 Data collection and extraction 96

19.3 Data conversion 96

19.4 Data authentication 96

19.5 Data submission 98

19.6 Data verification 98

19.7 Data verification periods 99

19.8 Complete data sets 99

19.9 Daily count classification 100

19.10 Data calibration 100

19.11 Data summaries 100

19.12 Data ownership and copyright 101

20 MONITORING SERVICE SPECIFICATION 104


20.2 Optional specifications 104

20.3 Schedule of quantities 104

20.4 Pay items for monitoring services 105

20.5 Pay items for road pavement tests 105

20.6 Monitoring service locations 105

20.7 Monitoring site characteristics 106

20.8 Monitoring service type, size and duration 106

20.9 New and existing monitoring sites 107

21 PAYMENT REQUIREMENTS 108


21.2 Contract rates 108

21.3 Rates to be inclusive 108

21.4 Payments for services 109

21.5 Changed monitoring durations 109



21.6 Discontinuation of monitoring services 110

APPENDIXES TO THE SPECIFICATIONS

Appendix A: Tolerance limits and intervals

Appendix B: Definition of Normal and Abnormal days

Appendix C: Monitoring system accuracy assessment method

Appendix D: Data verification tests

Appendix E: List of references

LIST OF TABLES

TABLE PAGE

Table 1 Alternative automatic traffic monitoring system types 32

Table 2 Measurement resolutions 35

Table 3 Tolerance limits for invalid detection 37

Table 4 Tolerance limits for vehicle categorization 38

Table 5 Tolerance intervals for vehicle speed, length and axle spacing 39

Table 6 HS-WIM Load and spacing resolutions 43

Table 7 HS WIM Tolerance intervals for load measurements 45

Table 8 LS WIM Axle load measurement resolution 47

Table 9 LS WIM Tolerance limits for load measurements 48

Table 10 Minimum sample size requirements for monitoring system assessments 54

Table 11 Pavement criteria applicable to concrete and asphalt pavements 62

Table 12 Clear distances for monitor housings or enclosures 66

Table 13 Alternative manual monitoring types 74

Table 14 Manual monitoring maximum allowable percentage errors 79



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Definitions

Unless inconsistent with the context, in these specifications, the following terms, words or

expressions shall have the meanings hereby assigned to them.

General

Employer: The person, organisation or authority who appoints the Service Provider for the

provision of traffic and WIM monitoring services. Normally, but not necessarily, the road

authority responsible for the road on which the service is required.

Road Authority: The organisation or government department that is responsible for the

road on which the monitoring service is provided.

Service Provider: The person or organisation that is appointed by the Employer to provide

the monitoring service. Monitoring services provided in terms of these specifications may

only be provided by Service Providers to whom valid Traffic and WIM Monitoring Service

Provider Certificates were issued.

System Supplier: The person or organisation that supplies the traffic and WIM monitoring

systems to Service Providers for use in the provision of monitoring services. The System

Supplier is not necessarily the manufacturer of equipment and may source equipment from

one or more manufacturers. The System Supplier may also provide the same services as

Service Providers, in which case, the requirements applicable to Service Providers will also

be applicable to the System Supplier.

Certification Organisation: The organisation that is responsible for and undertakes the

certification of Service Providers and monitoring systems.

Traffic and WIM Monitoring Service Provider Certificate: A certificate issued by the

Certification Organisation to a Service Provider that certifies that the Service Provider

complies with the requirements of these specifications for the provision of automatic

monitoring services and that the Service Provider may provide such services in terms of

these specifications.

Manual Traffic Monitoring Service Provider Certificate: A certificate issued by the

Certification Organisation to a Service Provider that certifies that the Service Provider

complies with the requirements of these specifications for the provision of manual traffic

monitoring services and that the Service Provider may provide such services in terms of

these specifications.

Traffic and WIM Monitoring System Certificate: A certificate issued by the Certification

Organisation to a System Supplier that certifies that a monitoring system complies with the

requirements of these specifications and that such a monitoring system may be used for

the provision of automatic monitoring services in terms of these specifications.

South African Standard Traffic Data Collection Format: The latest version of the COTO

TMH14 South African Standard Traffic Data Collection Format document.



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Statistical terms

Mean (arithmetic), average: First moment of a probability distribution (for the population

or a sample).

Standard deviation: Positive square root of the variance.

Variance: Second central moment of a probability distribution (for the population or a

sample).

Accuracy: Closeness or degree of agreement between a measured value and a reference

value accepted as the true or correct value.

Deviation: Difference between a measured value and a reference value accepted as the

true and correct value. Expressed as a percentage of the reference value.

Reference value: The value which is accepted as the true and correct value for a particular

characteristic.

Resolution: The smallest value of the measured parameter that a device is able to

discriminate within the measuring range. The resolution does not indicate the accuracy with

which a measurement is undertaken and a high resolution does not imply that the system

is accurate.

Tolerance limit: The maximum limit which may not be exceeded by a characteristic when

a very large number of observations, representative of the population, is made.

Tolerance interval: One half of a zero-centred interval in which at least a certain proportion

of the observations must fall when a very large number of observations representative of

the population is made.

Percent-within-Limits (PWL): The estimated or measured proportion of observations

which fall within the tolerance interval.

Calibration factor: A numerical factor which is used to adjust measurements to

compensate for systematic bias or error.

Calibration: Adjustment to a reference level of values obtained from a measuring device.

Monitoring site definitions

Monitoring site: A monitoring site is defined as a single location where all lanes of traffic

are monitored as specified by the Employer (subject to a maximum of 32 lanes). Unless

specified otherwise by the Employer, the following roadways and lanes are included in a

single monitoring site:

1) Double carriageway roads. Both carriageways are included in the site even if the

carriageways are located some distance apart.

2) Intersections and interchanges. All roadways passing through, or at the

intersections or interchanges are included in the site.

The Service Provider may utilise more than one monitoring system to monitor a site with a

large number of lanes, or where the lanes are located some distance apart.



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Monitoring day definitions

Normal traffic days: These are days during which the same (or similar) hourly traffic

patterns occur on a daily basis during most weeks in a year. These days exclude the other

classes of days defined below.

Abnormal days: These are days on which the traffic pattern is influenced by public and

school holidays (as well as other days influenced by such holidays). These days are defined

based upon known dates of holidays as specified in Appendix B to these specifications.

Devices

Weigh-In-Motion (WIM): Process of measuring the loads of a moving vehicle.

High-speed WIM (HS WIM): The process of measuring loads of vehicles that are travelling

at normal speeds on a road. The loads include dynamic forces resulting from the vehicle

motion.

Low-speed WIM (LS WIM): The process of measuring static loads of vehicles that are

travelling at low speed (typically lower than 15 km/h), usually outside the normal traffic flow.

The speeds are so low that the dynamic forces are considered to be negligible.

Sensor: A device that is used for sensing some object.

Axle sensor: A device that measures the presence of a wheel and/or axle.

Single/dual tyre sensor: A device that determines whether a wheel is fitted with a single

tyre or with dual tyres.

Wheel load sensor: A device which measures the wheel load of a vehicle.

Axle load sensor: A device which simultaneously measures the combined wheel load for

all wheels and tyres on an axle.

Weighbridge: A weighing device which measures the weight or static load of stationary

vehicles with a very high level of accuracy suitable for legal purposes.

Monitoring systems

Monitoring system: A generic term for any type of traffic or weigh-in-motion (WIM)

monitoring system consisting of all the sensors and equipment required to monitor traffic or

axle loads.

Traffic monitoring system: A monitoring system that is used for the monitoring of traffic

flow characteristics such as traffic counts and speeds (but not axle loads).

Traffic and HS WIM monitoring system: A system that is used for the monitoring of traffic

flow characteristics, as well as axle loads by means of a high-speed (HS) weigh-in-motion

device.

HS WIM monitoring system: A system that is used for the monitoring of axle loads by

means of a high-speed (HS) weigh-in-motion device (such as a screening station).

LS WIM monitoring system: A system that is used for the monitoring of wheel loads by

means of a low-speed (LS) weigh-in-motion device.



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Monitoring services

Monitoring service: A generic term for any type of traffic or weigh-in-motion (WIM)

monitoring service.

Automatic traffic and WIM monitoring services. Services in which traffic and WIM

monitoring are mainly undertaken by means of mechanical and electronic equipment,

although some manual assistance may be involved.

Manual traffic monitoring services. Services in which traffic monitoring is undertaken

manually by humans, although use may be made of mechanical and electronic devices

during the monitoring.

Traffic monitoring service: A service for the monitoring of traffic flow characteristics, such

as traffic counts and speeds by means of a Traffic Monitoring system.

Toll traffic monitoring service: A service for the monitoring of classified traffic counts at

a toll plaza by means of two or more independent Traffic monitoring subsystems.

Traffic and HS WIM monitoring service: A service for the combined monitoring of traffic

flow characteristics and axle loads by means of a Traffic and high-speed (HS) weigh-in-

motion Monitoring system.

HS WIM monitoring service: A service for the monitoring of axle loads by means of a

high-speed (HS) weigh-in-motion monitoring system (such as for screening purposes at a

weighbridge).

LS WIM monitoring service: A service for the monitoring of wheel loads by means of a

low-speed (LS) weigh-in-motion monitoring system.

Monitoring duration: The nominal duration over which a site must be monitored as

specified in these specifications.

Monitoring data

Good data: Data that have passed the verification tests of these specifications.

Suspect data: Data that have failed the verification tests of these specifications and which

require further investigation.

Bad data: Data that have failed the verification tests due to a failed monitoring system.

Uncertain data: Data that have failed the verification tests due to the geometry of the road

or the pavement surface.

Missing data: Includes bad data as well as data that have not been submitted to the

Employer or which were submitted late.

Complete data set: A data set for a specific monitoring period which does not contain any

missing or bad data (the data set contains only good or uncertain data).

Mass and load

According to the International System of Units (SI), forces and weights should be expressed

in N or kN while masses must be expressed in kg and Mg (ton). In terms of these

specifications, however, all loads and forces must be converted and expressed in terms of



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equivalent mass units (kg). The conversion must be undertaken with the standard value for

gravitational acceleration.

The definitions provided below are not related to those used for purposes of law

enforcement nor can the definitions be used for such purposes.

Gravitational acceleration: The acceleration caused by gravity. For the purposes of these

specifications, the standard value of 9.80665 m/s2 must be used.

Mass: Mass is a measure of the amount of material in an object measured in units of kg

(kilogram). Can be estimated by dividing the weight or static load (in units of N) of the object

by the gravitational acceleration (in units of m/s2).

Load: The load exercised by a moving or stationary vehicle. Consists of static and dynamic

load components. Converted to equivalent mass units of kg by dividing the load measured

in units of N by the gravitational acceleration (in units of m/s2).

Weight: The gravitational force acting on a body mass. Equivalent to the static load

exercised by a stationary vehicle.

Static load: Load exercised by a stationary vehicle. Equivalent to the weight of a vehicle.

Static load component: The static load component of the total load exercised by a moving

vehicle.

Dynamic load component: The non-static component of the total load exercised by a

moving vehicle.

Wheels

Wheel: An assembly of tyres on one side of an axle. An axle consists of one or more

wheels, while the wheels may consist of one or more tyres.

Wheel load: The load of one wheel of a moving vehicle. Consists of static and dynamic

load components.

Static wheel load: The load or weight of a wheel of a stationary vehicle.

Static wheel load component: The static or weight component of the load exercised by a

wheel of a moving vehicle.

Dynamic wheel load component: The dynamic load component of a load exercised by a

wheel of a moving vehicle.

Axles

Axle: A single assembly consisting of one or more wheels on the same axle, each wheel

consisting of one or more tyres.

Axle load: Sum of all the wheel loads of an axle of a moving vehicle. Consists of static and

dynamic load components.

Static axle load: The load or weight of an axle of a stationary vehicle.

Static axle load component: The static or weight component of the load exercised by an

axle of a moving vehicle.



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Dynamic axle load component: The dynamic load component of a load exercised by an

axle of a moving vehicle.

Axle groups

Axle group: A set of axles that are spaced (centre to centre) closer than a distance of

2.2 m between the centres of axles. An axle group is not necessarily related to an axle unit

on a vehicle.

Axle group axles: The axles included in an axle group.

Axle group load: The sum of all axle loads included in a group of axles of a moving vehicle.

Consists of static and dynamic load components.

Static axle group load: The sum of all axle loads included in a group of axles of a

stationary vehicle.

Gross vehicles

Gross vehicle load: The sum of all axle loads of a moving vehicle.

Gross vehicle mass (Static gross vehicle load): The sum of all axle loads of a stationary

vehicle.



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PREFACE

Traffic and Weigh-in-Motion (WIM) monitoring is undertaken with the purpose of measuring

and collecting various traffic and vehicle characteristics, such as traffic counts, operating


management, planning and design of road networks and infrastructure.

This document contains a functional specification for the provision of traffic and WIM

monitoring services by a Service Provider to an Employer. Provision is made for both

automatic and manual monitoring of traffic. Automatic monitoring is mainly undertaken by

means of mechanical or electronic equipment while manual monitoring is mainly

undertaken by humans.

Provision is a made in the specifications for the screening of heavy vehicles at weighbridges

but not for law enforcement applications. The specifications are not suitable for and may

not be used for such applications.

Automatic monitoring services provided in terms of these specifications may only be

provided by Service Providers (or System Suppliers) to whom valid Traffic and WIM

Monitoring Service Provider Certificates have been issued. These monitoring services may

only be provided using monitoring systems that carry valid Traffic and WIM Monitoring

System Certificates.

Manual monitoring services provided in terms of these specifications may only be provided

by Service Providers to whom valid Manual Traffic Monitoring Service Provider Certificates

have been issued. No certification of equipment or devices used for the provision of such

services is required.

The issuing of the above certificates will be the responsibility of and undertaken by a

Certification Organisation specified by the Employer.

A number of functional specifications for traffic monitoring and WIM systems are available

internationally, but local experience with these specifications has shown that they are not

always suitable for use in South Africa. The international specifications also do not cover

all the monitoring services that are required. The available specifications were, however

used as a basis for the development of the specifications provided in this document, but

adjusted for local application. The specifications include the following:

• ASTM, 2002, Standard specification for Highway Weigh-In-Motion (WIM) Systems

with User Requirements and Test Methods, Specification number E 1381-02,

United States.

• COST Technical Committee on Transport, 1999, COST 323 Weigh-in-Motion of

Road Vehicles, Final Report, European WIM Specification, Version 3.0,

August 1999.

In addition to the above international specifications, the specifications are also based on

the Standard Specifications for Traffic Data Collection Services of the South African

National Roads Agency Limited.

Scope of Specifications


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1 SCOPE OF SPECIFICATIONS

1.1 Background

Traffic and Weigh-in-Motion (WIM) monitoring is undertaken with the purpose of measuring

and collecting various traffic and vehicle characteristics, such as traffic counts, operating


management, planning and design of road networks and associated infrastructure, but may

also be used for other purpose such as toll traffic monitoring.

The scope of these specifications covers the provision of Traffic and WIM Monitoring

Services by a Service Provider to an Employer. The specifications cover all aspects of such

services, including but not limited to aspects such as traffic monitoring systems, computer

software, monitoring sites, monitoring site assessments, monitoring service specifications

and payment requirements. It also covers the certification of Service Providers and

monitoring systems and the issuing of certificates.

The deliverables of the monitoring services are the provision of traffic and WIM data and

related reports to the Employer in accordance with the requirements of these specifications.

The deliverables do not include the monitoring equipment, computers, software systems or

the construction of any other facilities required for such services, and such equipment and

facilities shall remain the property of the Service Provider and be removed at the

termination of a project (unless otherwise specified by the Employer). The Employer may,

however, make facilities available and require that the Service Provider use the facilities

provided by the Employer.

Provision is made in the specifications for the use of monitoring systems for the screening

of heavy vehicles at weighbridges but not for law enforcement. The specifications are not

suitable for law enforcement and the specifications may not be used for such purposes.

Differentiation is made in the specification between a) automatic traffic and WIM monitoring

services and b) manual traffic monitoring services. Automatic traffic and WIM monitoring

services mainly involve the use of mechanical or electronic equipment for the monitoring

while manual traffic monitoring services are those that are undertaken manually by humans.

1.2 Automatic traffic and WIM monitoring services

Automatic traffic and WIM monitoring services are those in which traffic and WIM monitoring

are mainly undertaken by means of mechanical and electronic equipment, although some

manual assistance may be involved. The scope of the specifications are limited to the

following automatic traffic and WIM monitoring services:

a) Traffic monitoring services. These services include the monitoring of traffic flow

characteristics, such as traffic volumes (counts) and speeds.



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b) Toll traffic monitoring services. These services include traffic monitoring at or near

to a toll plaza by means of two or more Traffic monitoring systems as described in

a) above.

c) Traffic and High-speed Weigh-In-Motion (HS WIM) monitoring services. These

services include the Traffic monitoring services as in a) above, as well as the

monitoring of axle loads of vehicles travelling under normal traffic conditions on a

road.

d) High-speed Weigh-In-Motion (HS WIM) monitoring services. These services are

limited to the monitoring of axle loads, and exclude the Traffic monitoring services

as described in a) above.

e) Low-speed Weigh-In-Motion (LS WIM) monitoring services. These services include

the monitoring of left and right wheel loads of vehicles travelling at low speeds

(lower than 10 km/h) to allow direct observations of static loads. These services do

not include the Traffic monitoring services in a) above.

1.3 Manual traffic monitoring services

Manual traffic monitoring services are those in which traffic monitoring is undertaken

manually by humans, although use may be made of mechanical and electronic devices

during the monitoring.

The scope of the specifications for the provision of manual traffic monitoring services is

limited to the observation of traffic volumes only. The manual traffic surveys of other traffic

characteristics such as speeds are not covered by the specifications.

1.4 SI System of units

The International System of Units (SI) applies to all measurements specified in, and

required by, these specifications, except where otherwise indicated in the specifications.

1.5 Overview of specifications

The specifications cover the following aspects of the traffic monitoring and WIM services:

Part 1: Certification and quality assurance requirements:

a) Certification requirements applicable to Service Providers and monitoring

systems are provided in Chapter 2 (Service provider and monitoring

system certification).

b) Quality assurance requirements applicable to System Suppliers of

automatic monitoring systems are provided in Chapter 3 (Traffic and WIM

Monitoring System Supplier quality assurance).

c) Quality assurance requirements applicable to Traffic and WIM Monitoring

Service Providers are provided in Chapter 4 (Traffic and WIM Monitoring

Service Provider quality assurance).



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d) Quality assurance requirements applicable to Manual Traffic Monitoring

Service Providers are provided in Chapter 5 (Manual Traffic Monitoring

Service Provider quality assurance).

Part 2: Automatic monitoring system requirements:

a) General requirements applicable to all automatic traffic and WIM

monitoring systems covered by these specifications are provided in

Chapter 6 (General automatic monitoring system requirements).

b) Requirements applicable to automatic monitoring systems are provided in

Chapter 7 (Automatic traffic monitoring system requirements).

c) Requirements applicable to High-speed WIM systems are provided in

Chapter 8 (HS WIM monitoring system requirements).

d) Requirements applicable to Low-speed WIM systems are provided in

Chapter 9 (LS WIM Monitoring system requirements).

e) Requirements for the assessment of automatic monitoring systems are

provided in Chapter 10 (Automatic monitoring system assessment).

Part 3: Automatic monitoring site and system Installation requirements:

a) Requirements for automatic monitoring sites are provided in Chapter 11

(Automatic monitoring site requirements).

b) Requirements for installed automatic monitoring systems are provided in

Chapter 12 (Installed automatic monitoring system requirements).

c) Requirements for the assessment of automatic monitoring sites and

installed monitoring systems are provided in Chapter 13 (Installed

automatic monitoring system assessments).

d) Requirements for work undertaken at sites are provided in Chapter 14 (Site

works requirements).

Part 4 Manual traffic monitoring requirements

a) Requirements for different manual monitoring methods are provided in

Chapter 15 (Manual traffic monitoring types).

b) Requirements for monitoring sites at which manual traffic monitoring is

undertaken are provided in Chapter 16 (Manual traffic monitoring site

requirements).

c) Requirements related to manual monitoring fieldworkers are provided in

Chapter 17 (Traffic monitoring fieldworker requirements).

Part 5: Monitoring service and data requirements:

d) Requirements related to the provision of monitoring (automatic and

manual) services are provided in Chapter 18 (Monitoring service

requirements).

e) Requirements for monitoring data (automatic and manual) are provided in

Chapter 19 (Monitoring data requirements).

Part 6: Service specification and payment requirements:

a) Requirements for the specification of monitoring services are provided in

Chapter 20 (Monitoring service specification).

b) Requirements for the payment of services are provided in Chapter 21

(Payment requirements).



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Part 7 Appendices to the specifications:

a) Methodologies for determining tolerance limits and intervals are provided

in Appendix A.

b) Definitions of Normal and Abnormal days are provided in Appendix B.

c) A method that must be followed in the assessment of automatic monitoring

system accuracies is described in Appendix C.

d) Data verification tests required for the verification of collected traffic and

WIM data are described in Appendix D.

e) A list of references is provided in Appendix E.

Part 1: Certification and Quality Assurance Requirements


- 5 -

Part 1

Certification and Quality

Assurance Requirements



- 6 -


Part 1 contains the requirements that are applicable to the certification of Service Providers

and monitoring systems, as well as quality assurance measures that must be implemented

by System Suppliers and Service Providers. These requirements are applicable to the

provision of automatic traffic and WIM monitoring services as well as manual traffic

monitoring services. The requirements are provided in the following chapters:

Chapter 2 Service provider and monitoring system certification.

Chapter 3 Traffic and WIM Monitoring System Supplier quality assurance.

Chapter 4 Traffic and WIM Monitoring Service Provider quality assurance.

Chapter 5 Manual Traffic Monitoring Service Provider quality assurance



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2 SERVICE PROVIDER AND MONITORING SYSTEM

CERTIFICATION

2.1 Certification requirements

It is a requirement of these specifications that all monitoring services provided in terms of

these specifications may only be provided by certified Service Providers using certified

traffic monitoring systems. The certification requirements differentiate between automatic

and manual services, as follows:

a) Automatic traffic and WIM monitoring services. All automatic traffic and WIM

monitoring services may only be provided by Service Providers to whom valid

Traffic and WIM Monitoring Service Provider Certificates were issued. Such

services may only be undertaken using monitoring systems which carry valid Traffic

and WIM Monitoring System Certificates.

b) Manual traffic monitoring services. All manual traffic monitoring services may

only be provided by Service Providers to whom valid Manual Traffic Monitoring

Service Provider Certificates were issued. No certification is required of equipment

used for the provision of such services.

It is a further requirement of these specifications that only Service Providers to whom the

above service provider certificates were issued may offer their relevant services in a tender

to the Employer. For the provision of automatic monitoring services, the offer may only

include monitoring systems which carry valid Traffic and WIM Monitoring System

Certificates and which will not be subject to a review for a period of at least one year after

the commencement of the monitoring project.

System Suppliers may also act as Service Providers in which case all the requirements

applicable to Service Providers will then be applicable to the System Suppliers, including

the certification requirements.

2.2 System Suppliers and Service Providers

A System Supplier is the person or organisation that supplies traffic and WIM monitoring

systems to Service Providers for the provision of monitoring services. The System Supplier

is not necessarily the manufacturer of the equipment, and may source equipment from one

or more manufacturers. The System Supplier may also provide the same services as

Service Providers, in which case the requirements applicable to Service Providers will also

be applicable to the System Supplier.

The Service Provider is the person or organisation that is appointed by the Employer to

provide the monitoring service. Such services must be provided using certified monitoring

systems provided by a System Supplier. The Service Provider may also certify and provide

the monitoring systems, in which case the requirements applicable to System Suppliers will

also be applicable to the Service Provider.



- 8 -

2.3 Certification organisation

The Employer will specify the Certification Organisation that may be used for the

certification of Service Providers and monitoring systems. In the absence of such a

specification, Agrément South Africa must be used for the certification.

The Certification Organisation will be responsible for and undertake the certification of

Service Provider and monitoring systems. The organisation will issue certificates that certify

that a Service Provider or a monitoring system complies with all the specified requirements

of these specifications, including those related to quality control.

2.4 Traffic and WIM Monitoring System Certificates

Traffic and WIM Monitoring System Certificates required for the provision of automatic

monitoring services will be issued by the Certification Organisation to System Suppliers. It

is the responsibility of System Suppliers to submit an application for certification to the

Certification Organisation.

Certificates will be issued for specific makes and models of monitoring systems, and a

separate certificate is required for each make or model. In situations where a monitoring

system consists of a combination of different components, the combination of components

will be considered to be a complete monitoring system. The components include both hard-

and software components, including system software as well as software that is used for

the post-processing of collected data. The certificate will list the combination of components

that form part of the system, including the system and post-processing software.

A monitoring system may contain optional components that may not be required for the

provision of a particular monitoring service. The certificate must list these components and

indicate the components that must be installed to provide a monitoring service.

The certificate will only be applicable to a particular make and model of a monitoring system

and set of software. Should any changes be implemented to the monitoring system

(including the software), the Certification Organisation will decide whether the change can

be accommodated by an existing certificate or whether a new certificate will be required.

This decision will be based on the extent of the changes that were made to the monitoring

system or software.

A Traffic and WIM Monitoring System Certificate will only be issued when the requirements

of the following chapters of these specifications have been fully complied with:

• Chapter 2 (Service provider and monitoring system certification).

• Chapter 3 (Traffic and WIM Monitoring System Supplier quality assurance).

• Chapter 6 (General automatic monitoring system requirements).

• Chapter 7 (Automatic traffic monitoring system requirements).

• Chapter 8 (HS WIM monitoring system requirements).

• Chapter 9 (LS WIM Monitoring system requirements).

• Chapter 10 (Automatic monitoring system assessment).

The requirements for the assessment of monitoring systems are specified in Chapter 10

(Automatic monitoring system assessment). The requirements provide for certification as

well as review of monitoring systems.



- 9 -

The continued validity of a certificate is subject to a review by the Certification Organisation

every five years. In addition to this review, the Certification Organisation may require one

additional review at any time during this five-year period. The certificate will only be

renewed during such a review when the requirements of the above chapters have been

fully complied with.

A Traffic and WIM Monitoring System Certificate will be cancelled by the Certification

Organisation when it is found that a monitoring system no longer complies with the

requirements of these specifications. When a certificate is cancelled, no monitoring service

may be provided using the monitoring system, even if the certificate issued to a Service

Provider has not been cancelled.

2.5 Traffic and WIM Monitoring Service Provider Certification

Traffic and WIM Monitoring Service Provider Certificates for the provision of automatic

monitoring services will be issued to Service Providers as well as System Suppliers that

also provide monitoring services. The certificate will only be issued for the use of specific

certified monitoring systems (one or more) that are provided by System Suppliers for the

provision of monitoring services. Where a Service Provider uses monitoring services that

are provided by different System Suppliers, a certificate will be required for each individual

System Supplier. It is the responsibility of Service Providers to obtain such certificates from

the Certification Organisation.

There must be a valid contractual agreement between the Service Provider and the System

Supplier covering the supply and use of monitoring systems. The validity of the Traffic and

WIM Monitoring Service Provider Certificate is subject to such an agreement being

continually in place. The certificate will immediately be cancelled by the Certification

Organisation when the agreement is cancelled by the System Supplier.

A Traffic and WIM Monitoring Service Provider Certificate will only be issued when the

following requirements are complied with:

a) There is a valid contractual agreement between the Service Provider and the

System Supplier covering the supply and use of monitoring systems that are

supplied by the System Supplier.

b) The requirements of the following chapters of these specifications:


• Chapter 4 (Traffic and WIM Monitoring Service Provider quality

assurance).

c) The Service Provider has technical personnel or sub-contractors that have

received training and passed all the assessments required by the System Supplier

as specified in Chapter 4 (Traffic and WIM Monitoring Service Provider quality

assurance).

Requirements for the procedure that must be followed for the assessment of Service

Providers are provided in this chapter. Requirements are provided for the certification, as

well as the review of Service Providers.

The continued validity of a Traffic and WIM Monitoring Service Provider Certificate is

subject to a review by the Certification Organisation every three years. In addition to this



- 10 -

review, the Certification Organisation may require one additional review at any time during

the three-year period.

The certificate will only be renewed during such a review when the above requirements, as

well as the requirements of the following chapters are fully complied with:

• Chapter 11 (Automatic monitoring site requirements).

• Chapter 12 (Installed automatic monitoring system requirements).

• Chapter 13 (Installed automatic monitoring system assessments).

The above assessments will only be required when the Service Provider has installed a

new monitoring system since the date on which the certificate was issued or previously

reviewed. The assessments will be undertaken by the Certification Organisation at one or

more monitoring system installations, selected either specifically or randomly by the

Certification Organisation. The requirements for the assessment of the installed monitoring

systems are specified in Chapter 13 (Installed automatic monitoring system assessments).

The Traffic and WIM Monitoring Service Provider Certificate will be cancelled by the

Certification Organisation if it is found that the Service Provider no longer complies with the

requirements of these specifications, or when the approval of a Service Provider is

withdrawn by the System Supplier.

2.6 Traffic and WIM Monitoring Service Provider Assessment

The requirements for the assessment of Traffic and WIM Monitoring Service Providers for

certification purposes are provided in this section. The issuing of a Traffic and WIM

Monitoring Service Provider Certificate to a Service Provider by the Certification

Organisation is subject to the condition that the Service Provider be assessed and found

to comply with the requirements of this chapter.

The Service Provider must submit evidentiary documentation to the Certification

Organisation that shows that the Service Provider complies with the requirements of the

following chapters of these specifications:


• Chapter 4 (Traffic and WIM Monitoring Service Provider quality assurance).

The evidentiary documentation must include the following:

a) The contractual agreement between the Service Provider and the System Supplier

for the supply and use of the monitoring systems.

b) Records of the quality assurance measures that are being implemented by the

personnel or sub-contractors of the Service Provider (as specified in Chapter 4

(Traffic and WIM Monitoring Service Provider quality assurance)).

c) Records showing the training received and assessments passed by the personnel

or sub-contractors of the Service Provider. Records must be provided for all the

technical personnel and sub-contractors of the Service Provider.

The Certification Organisation may additionally require interviews with selected (or all)

personnel or sub-contractors of the Service Provider as part of the assessment.

During the review of a Service Provider, the Certification Organisation will, in addition to

the above assessments, also undertake assessments of one or more installed monitoring



- 11 -

systems in accordance with the requirements of Chapter 13 (Installed automatic monitoring

system assessments).

2.7 System Supplier and Service Provider Contractual Agreement

It is a requirement of these specifications that there must be a valid contractual agreement

between the Traffic and WIM Monitoring Service Provider and the System Supplier covering

the supply and use of monitoring systems. The validity of the Traffic and WIM Monitoring

Service Provider Certificate is subject to such an agreement being continually in place.

The agreement must show that the Service Provider is approved by the System Supplier.

The specific monitoring systems for which such approval is given must be specified in the

agreement. The agreement must also specify the conditions under which the approval and

the agreement may be cancelled by the System Supplier.

The agreement must also cover all the obligations of the Service Provider and the System

Supplier in terms of the requirements of these specifications.

2.8 Manual Traffic Monitoring Service Provider Certification

Manual Traffic Monitoring Service Provider Certificates will be issued to Service Providers

who comply with the requirements of Chapter 5 (Manual Traffic Monitoring Service Provider

quality assurance) of these specifications.

In its application to the Certification Organisation for certification, the Service Provider must

submit evidentiary documentation showing that the Service Provider complies with the

requirements of Chapter 5 (Manual Traffic Monitoring Service Provider quality assurance)

of these specifications. The evidentiary documentation must include the following:

a) Manuals used by the Service Provider setting out the quality assurance measures

implemented by the Service Provider.

b) Records of the quality assurance measures that are being implemented by the

personnel or sub-contractors of the Service Provider.

c) Records showing the training received and assessments passed by the personnel

or sub-contractors of the Service Provider. Records must be provided for all the

technical personnel and sub-contractors of the Service Provider.

The Certification Organisation may additionally require interviews with selected (or all)

personnel or sub-contractors of the Service Provider as part of the assessment.

The continued validity of a Manual Traffic Monitoring Service Provider Certificate is subject

to a review of the Service Provider by the Certification Organisation every three years. In

addition to this review, the Certification Organisation may require one additional review at

any time during the three-year period.

The certificate will be cancelled by the Certification Organisation when it is found that the

Service Provider no longer complies with the requirements of these specifications. When a

certificate is cancelled, no further manual traffic monitoring services may be provided by

the Service Provider.



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3 TRAFFIC AND WIM MONITORING SYSTEM SUPPLIER

QUALITY ASSURANCE

3.1 Quality assurance requirements

The requirements for quality control measures that must be implemented by System

Suppliers are provided in this chapter. These measures must be in place before an

application can be made for the certification of the monitoring systems. The requirements

of this chapter apply to monitoring systems used in the provision of automatic traffic

monitoring services and not to equipment used for manual traffic monitoring.

It is the responsibility of the System Supplier to implement quality assurance measures

aimed at ensuring the following:

a) That every monitoring system supplied by the System Supplier will comply with the

requirements of these specifications.

b) That monitoring systems are used, maintained and operated by the Service

Provider in accordance with the requirements of the System Supplier, as well as

the requirements of these specifications.

The System Supplier must develop manuals that describe and specify the required quality

assurance measures to be implemented by the System Supplier as well as the Service

Provider. Copies of these manuals must be submitted to the Certification Organisation for

approval when an application is made for certification. Copies of the manuals must also be

made available to the Employer.

In all instances, the System Supplier must apply the codes of practice for quality systems

as outlined in SABS ISO 9000 to SABS ISO 9004.

3.2 System supplier quality assurance measures

The System Supplier is responsible for implementing quality assurance measures that are

aimed at ensuring that every monitoring system supplied by the System Supplier complies

with the requirements of these specifications.

The System Supplier must have a manual that sets out the quality assurance measures,

and this manual must be used by all the personnel in the organisation. A copy of this manual

must be submitted to the Certification Organisation for approval when an application is

made for a monitoring system certificate. The System Supplier must also maintain records

as evidence that the manual is being implemented.

The following monitoring system quality assurance measures are required:

a) Management systems. The purpose of the management systems is to ensure that

quality assurance is enforced at all levels of the organisation, including any external

organisations involved in the supply chain. Instructions must be issued with regard

to the following:



- 13 -

i) The responsibilities of management personnel responsible for ensuring

that the quality assurance system is effectively implemented in

the organisation.

ii) The responsibilities of all the personnel in the organisation with regard to

quality assurance.

b) Monitoring system quality assurance. Procedures must be instituted that will

ensure that every monitoring system supplied by the System Supplier complies

with the requirements of these specifications. Instructions and procedures must be

issued with regard to the following:

i) Inspections and tests of monitoring systems that are undertaken, including

the testing equipment used for the tests.

ii) Procedures for ensuring that the testing equipment is controlled and

calibrated on a regular basis. Certificates or other proof of calibration must

be kept on record and made available for inspection.

iii) Procedures that must be followed when it is found that a monitoring system

does not comply with the requirements. Steps must be described that must

be followed to prevent the unintended use or delivery of such systems.

Records must be kept of equipment that fails the tests.

iv) Records of all testing and inspections must be signed by a designated

responsible person in the organisation, filed and made available for

inspection.

c) Monitoring system identification. Each supplied monitoring system must be

identified by means of a unique serial number (or numbers) to ensure that the

system can be traced. Detailed records must be kept of these numbers, including

the particulars of the Service Provider to whom the systems were issued

or provided.

d) Internal quality audits. The System Supplier must conduct regular internal audits to

ensure that the quality control measures are implemented. The procedures that

must be followed during such audits must be specified, as well as any records that

must be completed.

e) Records. All records must ensure and show that the quality assurance system is

operating effectively and that the supplied monitoring systems comply with the

requirements of these specifications. Instructions and procedures must also be

provided on the filing and control of the records. The record system must meet the

following requirements:

i) Records must be traceable to a particular monitoring system.

ii) The records must remain legible for the duration that a monitoring system

is in use.

iii) Records must be filed and indexed for ease of retrieval.



- 14 -

3.3 Service provider quality assurance measures

The System Supplier is responsible for the implementation of quality assurance measures

that are aimed at ensuring that Service Providers and their personnel and sub-contractors

are competent and continue to be competent to use the monitoring systems in accordance

with the requirements of these specifications. These measures must also be implemented

when the System Supplier also provides monitoring services.

The specific responsibilities of the System Supplier in this regard are as follows (more

details of these responsibilities are provided in the following sections of this chapter):

a) Service provider monitoring system manuals. The development of manuals and

specifications for use by the Service Provider for the installation, maintenance and

operation of a monitoring system.

b) Service provider quality assurance manuals. The development of manuals for use

by the Service Provider for the implementation of quality assurance measures.

c) Service provider training and assessment. The training and assessment of the

technical personnel and sub-contractors of the Service Provider to ensure that they

are competent to install, maintain and operate the monitoring systems. The System

Supplier must prepare a manual that will be used for such training and assessment.

The System Supplier must also keep records of all persons that have received

training and supply details of whether such persons were assessed to be fully

competent in the use of the monitoring system.

d) Monitoring system inspection and assessment. The regular inspection and

assessment of monitoring systems installed by the Service Provider. The System

Supplier must prepare a manual that will be used for such inspection and

assessment. The System Supplier must also keep records of the inspections and

assessments, together with the findings of such inspections and assessments.

Copies of all manuals must be submitted to the Certification Organisation for approval when

an application is made for a monitoring system certificate. Copies of the manuals must also

be made available to the Employer.

Copies of the service provider training and assessments, as well as the monitoring system

inspection and assessment records must be made available and submitted to the

Certification Organisation.

3.4 Service provider monitoring system manuals

The System Supplier must develop the manuals listed below and make these manuals

available to the Service Provider:

a) Installation manual. This manual must provide full details and specifications for the

installation of a monitoring system, together with all the quality assurance

measures that must be implemented during the installation. The manual must cover

aspects such as the following:

i) Any drawings that may be required for the installation of the system.

ii) Specifications for the installation of the system, together with relevant

dimensions and tolerances.

iii) Procedures and steps to be followed during the installation of the system.



- 15 -

iv) Equipment, tools and materials that must be used for the installation of the

system and, where appropriate, the use of such equipment, tools

or materials.

v) Tests that must be undertaken at various stages to test the installed

components.

vi) Quality assurance measures that must be instituted by the Service

Provider and that must be followed during the installation of the system.

vii) Records that must be kept of the installation of the system.

b) Maintenance manual. This manual must provide full details for the maintenance of

a monitoring system, together with all the quality assurance measures that must

be implemented. The manual must cover aspects such as the following:

i) Methods for the checking of the system and the identification of possible

faults or errors.

ii) Procedures and steps to be followed to address any of the identified faults.

iii) Equipment and tools that must be used for the identification of the faults

and maintenance of the system.

iv) Tests that must be undertaken to ensure that the maintenance actions

were successful.

v) Quality assurance measures that must be instituted and followed by the

Service Provider during the maintenance of the system.

vi) Records that must be kept of the maintenance of the system.

c) Operations manual. This manual must provide full details for the operation of a

monitoring system, together with all quality assurance measures that must be

implemented while the system is in operation. The manual must cover aspects

such as the following:

i) Any calibration that may be required and which must be undertaken.

ii) Setting up the monitoring system to undertake the monitoring service.

iii) Quality assurance measures that must be instituted by the Service

Provider and that must be followed during the operation of the system.

iv) Records that must be kept of the operation of the system.

3.5 Service provider quality assurance manuals

The System Supplier must develop the quality assurance manuals listed below and make

these manuals available to the Service Provider:


quality assurance is enforced at all levels of the Service Provider organisation,

including any external organisations or sub-contractors that may be used by the

Service Provider for the provision of the monitoring services.

b) Monitoring service quality assurance. Procedures must be instituted that will

ensure that all the monitoring services provided by the Service Provider comply

with the requirements of these specifications. Instructions and procedures must be




- 16 -

i) Inspections and tests that must be undertaken during the installation,

maintenance and operation of monitoring systems, including any testing

equipment used for the tests.

ii) Procedures to ensure that testing equipment is controlled and calibrated

on a regular basis. Certificates or other proof of calibration must be kept

on record and made available for inspection.

iii) Procedures that must be followed when it is found that a monitoring

installation does not comply with the requirements or specifications.

iv) Records of all testing and inspections that must be maintained by the

Service Provider.

c) Internal quality audits. The Service Provider must conduct regular internal audits

to ensure that the quality control measures are implemented. The procedures that

must be followed during such audits must be specified, as well as any records that

must be completed.

d) Records. All records must ensure and show that the quality assurance system is

operating effectively and that monitoring services comply with the requirements of

these specifications. Instructions and procedures must also be provided regarding

the filing and control of the records. The record system must ensure the following:

i) Records must be traceable to particular tasks that have been performed.

ii) The records must remain legible for the duration that a monitoring service

is provided.

iii) Records must be filed and indexed for ease of retrieval.

3.6 Service provider training and assessment

The System Supplier is responsible for the training and assessment of the technical

personnel and sub-contractors of a Service Provider to ensure that they are competent to

install, maintain and operate the supplied monitoring systems. Training and assessment

must be undertaken regarding the following aspects related to the use of monitoring

systems:

a) Installation of monitoring systems.

b) Maintenance of monitoring systems.

c) Operation of monitoring systems.

d) Quality assurance of monitoring systems.

Each personnel member (including those of sub-contractors) that has received training

must be assessed to determine if the member is fully competent to independently undertake

any work involved with one or more of the abovementioned aspects. Only members that

are considered by the System Supplier to be fully competent to undertake the work may

pass the assessment. Partial competency may not be accepted.

A record must be kept of all persons that received the training and that have passed the

assessment. The records of such persons must be made available and submitted (on

request) to the Certification Organisation.



- 17 -

A manual must be prepared by the System Supplier that will be used in the training and

assessment of personnel and sub-contractors of the Service Provider. This manual must

cover the following aspects:

a) Programmes, contents and training material that will be used in the training of the

different aspects related to the use of the monitoring systems.

b) Assessment methods and tests, together with criteria for testing the competency

of personnel members.

3.7 Installed monitoring system inspection and assessment

The System Supplier must institute a programme for the regular inspection and assessment

of the monitoring systems that have been installed and are being operated by the Service

Provider. The purpose of the inspections and assessments is to determine whether the

monitoring systems have been installed and are being maintained, operated and managed

in accordance with the requirements of these specifications, including those related to

quality assurance.

The System Supplier must inspect and assess a minimum of one (1) monitoring system

installation per annum for the Service Provider. The systems must be selected randomly

from a list of installations that have been installed by the Service Provider since the previous

review. No inspection or assessment is required when the Service Provider has not

installed a system during the previous year.

A record must be kept of all the inspections and assessments irrespective of whether an

installation has failed or passed the assessments. The records of such inspections and

assessments, together with the findings of the inspections and assessments must be made

available and submitted to the Certification Organisation when requested.

A manual must be prepared by the System Supplier for use by personnel of the System

Supplier during the inspection and assessment of installations. The manual must cover all

the aspects related to such inspections and assessments, including all the tests that must

be undertaken during such inspections and assessments.



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4 TRAFFIC AND WIM MONITORING SERVICE

PROVIDER QUALITY ASSURANCE


This chapter provides the requirements for the quality control measures that must be

implemented by a Traffic and WIM Monitoring Service Provider. These are in addition to

any additional quality control measures that may be required by the System Supplier. The

requirements of this chapter do not apply to Manual Traffic Monitoring Service Providers.

All quality control measures specified in this chapter must be in place before an application

can be made for the certification of a Traffic and WIM Monitoring Service Provider. This

includes the requirement that the Service Provider must have personnel or sub-contractors

that have received all the training and passed all the assessments that are required by the

System Supplier.

In all instances, the Service Provider must apply the codes of practice for quality systems


4.2 Quality assurance measures

The Traffic and WIM Monitoring System Supplier is responsible for making the following

manuals (as specified in Chapter 3 (Traffic and WIM Monitoring System Supplier quality

assurance)) available to the Service Provider who will be responsible for implementing the

requirements as set out in the manuals:

a) Service provider monitoring system manuals for the installation, maintenance and

operation of a monitoring system.

b) Service provider quality assurance manuals for the implementation of quality

assurance measures.

The Service Provider must have a system in place for the implementation of all the required

quality assurance measures. This system must be in place before an application can be

made for the certification of a Service Provider.

The quality assurance system must provide for the maintenance of records that must be

kept as evidence that the quality assurance measures are being implemented by the

personnel or sub-contractors of the Service Provider. These records include the following:

a) Management systems. Record must be kept of instructions that have been issued

to personnel with regard to:

i) The responsibilities of management personnel tasked with ensuring that

the quality assurance system is effectively implemented in the

organisation.

ii) The responsibilities of all personnel in the organisation (including sub-

contractors) with regard to quality assurance.



- 19 -

b) Monitoring service quality assurance. Records of all testing and inspections

undertaken during the installation, maintenance and operation of monitoring

systems. Such records must be signed by a designated responsible person, filed

and made available for inspection by the Certification Organisation.

c) Internal quality audits. Records of regular internal audits to ensure that the quality

control measures are implemented by all personnel and sub-contractors of the

Service Provider.

4.3 Personnel training and assessment

It is a requirement of these specifications that monitoring services may only be provided by

a Traffic and WIM Monitoring Service Provider whose technical personnel and sub-

contractors have received all the training and have passed all the assessments required by

the System Supplier. It is a further requirement that only personnel and sub-contractors

that have received such training and have passed such assessments may be used for the

provision of the monitoring services.

The Service Provider must keep records of all persons that received the training and that

have passed the assessment. These records are in addition to the records kept by the

System Supplier. The records of such persons must be made available and submitted to

the Certification Organisation when an application is made for certification. The Traffic and

WIM Monitoring Service Provider Certificate will only be issued to a Service Provider whose

personnel and sub-contractors have received the training and passed the assessments

required by the System Supplier.



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5 MANUAL TRAFFIC MONITORING SERVICE

PROVIDER QUALITY ASSURANCE


Requirements for the quality control measures that must be implemented by the Manual

Traffic Monitoring Service Provider in the provision of manual traffic monitoring services are

provided in this chapter. These quality control measures must be in place before an

application is made for the certification of a Manual Traffic Monitoring Service Provider.

This includes the requirement that the Service Provider must have personnel or sub-

contractors that have received the training and passed the assessments specified in this

chapter.

The Service Provider must develop manuals that describe and specify the quality

assurance measures implemented by the Service Provider. Copies of these manuals must

be submitted to the Certification Organisation for assessment when an application is made

for certification. Copies of the manuals must also be made available to the Employer.

In all instances, the Service Provider must apply the codes of practice for quality systems


5.2 Quality assurance measures

The Service Provider is responsible for the implementation of a quality assurance system

that is aimed at ensuring that manual traffic monitoring is undertaken in accordance to the

requirements of these specifications.

The specific responsibilities of the Service Provider in this regard are as follows (more

details of these responsibilities are provided in the following sections of this chapter):

a) Quality assurance manuals. The development of quality assurance manuals and

the implementation of the manuals.

b) Training and assessment. The training and assessment of technical personnel and

sub-contractors aimed at ensuring that they are competent to undertake manual

traffic monitoring. A manual must be prepared and used for such training and

assessment. The Service Provider must also keep records of all persons that have

received training and supply details of whether such persons were assessed to be

fully competent in the use of the monitoring system.

Copies of all manuals as well as training and assessment records must be submitted to the

Certification Organisation for approval when an application is made for a monitoring system

certificate. Copies of the manuals and records must also be made available to the

Employer.



- 21 -

5.3 Quality assurance manuals

The Service Provider must develop the following quality assurance manuals and ensure

that these manuals are implemented by the personnel of the Service Provider:


quality assurance is enforced at all levels of the Service Provider organisation,

including any external organisations or sub-contractors that may be used by the

Service Provider for the provision of the traffic monitoring services. Specific

instructions and procedures must be issued with regard to the following:

i) The responsibilities of management personnel responsible for ensuring

that the quality assurance system is effectively implemented in

the organisation.

ii) The responsibilities of all the personnel in the organisation with regard to

quality assurance.

b) Monitoring service quality assurance. Quality assurance measures must be

instituted that will ensure that all traffic monitoring services provided by the Service

Provider comply with all of the requirements of these specifications. These

measures must include inter alia the following:

i) Checks aimed at ensuring that the monitoring team has all the data forms

and equipment that is required for the monitoring. These checks must be

made prior to departure to the monitoring site.

ii) Tests that must be undertaken on all equipment (including writing utensils)

to ensure that equipment is in good working order. These tests must be

undertaken prior to departure to the monitoring site.

iii) Measures aimed at ensuring that a sufficient number of trained

fieldworkers and equipment are available for the provision of a traffic

monitoring service.

iv) Measures aimed at ensuring that the monitoring is undertaken at the

correct location.

v) Measures aimed at ensuring that the monitoring is undertaken correctly

and in accordance to the requirements of these specifications.

vi) Measures for ensuring that traffic and other data are captured correctly

and submitted to the Employer in accordance to the requirements of these

specifications.

c) Internal quality audits. The Service Provider must conduct regular internal audits

to ensure that the quality control measures are implemented in the organisation.

The procedures that must be followed during such audits must be specified, as well

as any records that must be completed. Procedures and instructions must be


i) Management level quality assurance measures.

ii) Monitoring service quality assurance measures.

iii) Records of implemented quality assurance measures.

d) Records. Records must ensure and show that the quality assurance system is

operating effectively and that the monitoring services comply with the requirements

of these specifications. The following records must be maintained by the Service

Provider:



- 22 -

i) Records that shows that management level quality assurance measures

are implemented by the organisation.

ii) Records that shows the quality assurance measures that were

implemented for each traffic monitoring service undertaken by the Service

Provider.

iii) Records of internal audits

Instructions and procedures must also be provided regarding the filing and control

of the records. The record system must ensure the following:

i) Records must be traceable to particular quality assurance measures that

have been performed.

ii) Records must be filed and indexed for ease of retrieval.

5.4 Training and assessment

It is a requirement of these specifications that only personnel or sub-contractors that have

received the required training and have passed the required assessments may be used for

the provision of the monitoring services. The Service provider is responsible for the training

and assessment of the personnel and sub-contractors.

A training manual must be prepared by the Service provider that will be used in the training

and assessment of personnel and sub-contractors of the Service Provider. This manual

must cover the following aspects:

a) Programmes, contents and training material that will be used in the training in all

aspects related to traffic monitoring. Provision must be made for theoretical as well

as practical training of personnel.

b) Assessment methods and tests, together with criteria for testing the competency

of personnel members.

The training must cover the following aspects:

a) Monitoring service quality assurance procedures.

b) The different manual traffic monitoring types and requirements pertaining to each

monitoring type as specified in Chapter 15 (Manual traffic monitoring types).

c) The requirements pertaining to traffic monitoring sites specified in Chapter 16

(Manual traffic monitoring site requirements).

d) Requirements applicable to manual traffic monitoring fieldworkers as specified in

Chapter 17 (Traffic monitoring fieldworker requirements).

e) Requirements for the provision of manual monitoring services as specified in

Chapter 18 (Monitoring service requirements).

f) Requirements for collection and submission of manual monitoring data as specified

in Chapter 19 (Monitoring data requirements).

Each personnel member (including those of sub-contractors) that has received training

must be assessed to determine if the person is fully competent to independently undertake

any work involved with one or more of the abovementioned aspects. Only persons that are

considered by the Service Provider to be fully competent to undertake the work may pass

the assessment. Partial competency may not be accepted.



- 23 -

The Service Provider must keep records of all persons that received the training and that

have passed the assessment. The records of such persons must be submitted to the

Certification Organisation when an application is made for certification. The Manual Traffic

Monitoring Service Provider Certificate will only be issued to a Service Provider whose

personnel and sub-contractors have received training and passed the required

assessments.

Part 2: Automatic Monitoring System Requirements


- 24 -

Part 2

Automatic Monitoring System

Requirements



- 25 -


Part 2 contains the requirements that are applicable to the monitoring systems that may be

used for the provision of traffic monitoring and WIM services. These requirements are

applicable to the provision of automatic traffic and WIM monitoring services and not to

manual traffic monitoring services. These requirements are provided in the following

chapters:

Chapter 6 General automatic monitoring system requirements.

Chapter 7 Automatic traffic monitoring system requirements.

Chapter 8 HS WIM monitoring system requirements.

Chapter 9 LS WIM Monitoring system requirements.

Chapter 10 Automatic monitoring system assessment.



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6 GENERAL AUTOMATIC MONITORING SYSTEM

REQUIREMENTS

6.1 General requirements

This chapter provides a number of general requirements applicable to the monitoring

systems used in the provision of automatic monitoring services. The requirements are

aimed at ensuring that the systems are capable of undertaking the required monitoring and

that data will be of an acceptable quality.

The requirements are applicable to all types of monitoring systems that are described in

these specifications (traffic and WIM). Additional requirements are provided in subsequent

chapters of these specifications.

6.2 Environmental conditions

The traffic and WIM monitoring system must be able to operate under the following

environmental conditions:

a) It must be possible to install pavement sensors in or on all types of concrete and

asphalt pavements found in South Africa. When monitoring is required on a gravel

road, it must also be possible to install the sensors in or on the gravel pavement.

b) The system must be able to operate without degradation under ambient

temperatures in the range between -10C to +60C, a relative humidity in the range

of 0 to 90% (not condensing) and during adverse weather conditions.

c) Any sensors that are installed on the road pavement must be able to operate

without degradation or loss of sensitivity under road-surface temperatures in the

range between -10C to +80C and a relative humidity in the range of 0 to 100%.

These include sensors that are supported by the pavement and which may be

affected by the pavement modulus of elasticity that could vary with temperature.

d) The monitoring system and sensors must be protected against, or must be

insensitive to adverse effects that may be caused by vermin, moisture, water, ice,

fuel, oil, salt, dust, electrical power spikes, as well as any external electrical or

magnetic fields.

6.3 Environmental requirements

The monitoring system may not have the following environmental impacts:

a) The system and sensors may not cause undesirable environmental effects, such

as the leaking or spillage of hazardous, toxic or undesirable materials, fluids or

gases into the environment.



- 27 -

b) The system and sensors may not be aesthetically or visually obtrusive. All parts of

the system must, as far as practically possible, be hidden from view or blended

with the background. There may not be any visible loose wiring or parts protruding

from the road pavement, ground surface or equipment housing.

6.4 Operational requirements

The monitoring system must comply with the following operational requirements:

a) The system and sensors must be protected against acts of vandalism, criminal or

malicious mischief and theft.

b) Where sensors are installed in or on the road pavement, such sensors must remain

fixed under all traffic flow and environmental conditions until their removal. The

sensors must be able to withstand crossing by tracked vehicles or deflated tyres

that are legally allowed on public roads.

c) The system and sensors may not create a road and traffic hazard, nor endanger

the safety of people, animals, vehicles and property. Traffic safety requirements for

the location of equipment housing are provided in Chapter 12 (Installed automatic

monitoring system requirements).

6.5 Power provision requirements

The following power related provision requirements apply to the monitoring system:

a) In terms of these specifications, it is the responsibility of the Service Provider to

obtain or procure the power required to operate a monitoring system.

b) Any power source may be used, but the power supply must be sufficient to allow

continuous operation of the monitoring system over the duration of a

monitoring service.

6.6 Data recording capabilities

The monitoring system must have the following data recording capabilities:

a) The system must be capable of recording individual vehicle data as specified in the

South African Standard Traffic Data Collection Format, including all the data

required to produce the header and other required records.

b) Traffic monitoring and HS WIM systems must have sufficient capacity to record

data for all vehicles passing a site for the periods between data extractions.

c) Recorded data may not be lost when power supply to the system is interrupted or

when the system is switched off.



- 28 -

6.7 Data extraction requirements

The monitoring system must have the following data extraction capabilities:

a) The system must allow data extraction while in operation without affecting the data

collection and processing capabilities of the system, irrespective of the method

according to which data are extracted.

b) Any method may be used for the extraction and supply of data, subject to the

following requirements:

i) No data may be lost as a result of the extraction method.

ii) The data must be supplied within the time period as specified in Chapter

19 (Monitoring data requirements).

6.8 Post-processing software requirements

Traffic data may be processed by means of software provided as part of the monitoring

equipment or by means of post-processing software on completion of the monitoring. Both

types of software are considered to form part of a monitoring system and must be

certificated as part of the monitoring system as specified in Chapter 2 (Service provider and

monitoring system certification), The post-processing software includes all software that

are used to process traffic data up to the submission of data to the Employer.



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7 AUTOMATIC TRAFFIC MONITORING SYSTEM

REQUIREMENTS

7.1 System requirements

This chapter provides the requirements for automatic monitoring systems that may be used

for the provision of Traffic monitoring, Toll traffic monitoring, as well as Traffic and HS WIM

Monitoring services. These requirements are in addition to the general requirements

provided in Chapter 6 (General automatic monitoring system requirements).

Traffic monitoring systems are used to measure traffic flow characteristics, such as traffic

volumes (counts) and the operating speeds of vehicles travelling under normal conditions

on a roadway without interrupting the flow of traffic.

For Toll traffic monitoring services, two or more Traffic monitoring systems operating

independently must be used to monitor the traffic. The specifications in this chapter are

applicable to each of the individual monitoring systems.

7.2 Traffic monitoring system types

Differentiation is made in these specifications between different automatic traffic monitoring

types and accuracy classes. The Employer will specify the monitoring type and accuracy

class when requiring an automatic traffic monitoring service.

Provision is made for the following automatic monitoring system types (A to E) listed below.

For each type, provision is made for two accuracy levels (1 and 2). The system types and

accuracy levels are as follows:

a) Type A traffic monitoring systems with vehicle, speed, axle and single/dual tyre

detection. These systems provide for the monitoring of characteristics such as

vehicle lengths, speeds, number of axles, axle spacing and tyre configuration

(single or dual). Differentiation is made between the following two sub-types:

i) Type A1 systems with the highest levels of detection and vehicle

classification accuracy. Recommended for traffic monitoring where the

highest levels of accuracy are required.

ii) Type A2 systems with relatively high levels of detection and vehicle

classification (categorization) accuracy. Recommended for long-term

traffic monitoring where relatively high levels of accuracy are required. Also

recommended for HS WIM installations.

b) Type B traffic monitoring systems with vehicle, speed and axle detection but

without single/dual tyre detection. These systems provide for the monitoring of

characteristics such as vehicle lengths, speeds, number of axles and axle spacing,

but not tyre configuration. Differentiation is made between the following two sub-

types:



- 30 -

i) Type B1 systems with the highest level of detection and a relatively high

level of vehicle classification (categorization) accuracy. Recommended for

toll traffic monitoring where the highest level of vehicle detection accuracy

is required but not the highest level of vehicle classification accuracy.

ii) Type B2 systems with a relatively high level of detection and a medium to

high level of vehicle classification (categorization) accuracy.

Recommended for long-term traffic monitoring where a relatively high

detection level is required, but medium to high levels of vehicle

classification accuracy are acceptable. Also recommended for HS WIM

installations (but only for the lanes in which HS WIM monitoring is

undertaken).

c) Type C traffic monitoring systems with vehicle and speed detection but without axle

and single/dual tyre detection. These systems provide for the monitoring of

characteristics such as vehicle lengths and speeds but not of number of axles, axle

spacing and tyre configuration. Differentiation is made between the following two

sub-types:

i) Type C1 systems with a relatively high level of detection and a medium to

low level of vehicle classification (categorization) accuracy and where axle

data are not required. Recommended for long-term traffic monitoring, as

well as short-term traffic monitoring on roads where relatively high

detection levels are required but medium to low vehicle classification

accuracy are acceptable.

ii) Type C2 systems with a medium level of detection and a relatively low level

of vehicle classification (categorization) accuracy and where axle data are

not required. Recommended for short-term traffic monitoring on roads

where a medium level of detection and relatively low vehicle classification

accuracy is acceptable.

d) Type D traffic monitoring systems without vehicle length, speed, axle and

single/dual tyre detection. These are basic systems which only provide for traffic

counts and not for the monitoring of characteristics such as vehicle lengths,

speeds, number of axles, axle spacing and tyre configurations. Vehicle

classification may be based on an assumed average speed for the site but the

accuracy of such classification will be relatively poor. Differentiation is made

between the following two sub-types:

i) Type D1 systems with a medium level of detection accuracy and either no

vehicle classification (categorization) or a low level of vehicle classification

(categorization) accuracy. Recommended for short-term traffic monitoring

on roads where a medium level of detection accuracy is acceptable, but

where vehicle classification is either not required, or a low level of accuracy

is acceptable.

ii) Type D2 systems with a relative low level of detection accuracy and either

no vehicle classification (categorization) or a low level of vehicle

classification accuracy. Recommended for short-term traffic monitoring on

roads where relatively low levels of detection accuracy are acceptable.

Vehicle classification is either not required or a low level of accuracy is

acceptable.



- 31 -

e) Type E traffic monitoring systems without vehicle and single/dual tyre detection but

with speed and axle detection. These systems provide for the monitoring of

characteristics such as number of axles and axle spacing, but not tyre

configuration. Vehicle units and lengths cannot be directly detected or measured

but can be indirectly identified or estimating from axle spacing data. Differentiation

is made between the following two sub-types:

i) Type E1 systems with a relatively high level of detection and a medium to

low level of vehicle classification accuracy. Recommended for long-term

traffic monitoring, as well as short-term traffic monitoring on roads where

relatively high detection levels are required but medium to low vehicle

classification accuracy are acceptable.

ii) Type E2 systems with relatively low levels of detection and vehicle

classification accuracy. Recommended for short-term traffic monitoring on

roads where a medium level of detection and relatively low vehicle

classification accuracy is acceptable.

The detection requirements for the different monitoring system types are summarised in

the following table:

System Type Veh length Speed Axle Tyre Conf

A1/A2

B1/B2

C1/C2

D1/D2 (*1) (*2) (*3)

E1/E2 (*4)

(*1) May be estimated using an assumed average speed for the site

(*2) An average speed may be assumed for the site

(*3) Vehicle units may be identified from axle detectors

(*4) Vehicle units and lengths may be identified/estimated from axle data

In the absence of a traffic monitoring system type and accuracy level specification by the

Employer, the following monitoring systems and accuracy levels must be used:

• Type B1 monitoring systems for toll traffic monitoring.

• Type B2 monitoring systems when integrated with HS WIM monitoring (but only for

lanes in which HS WIM monitoring is undertaken).

• Type C1 monitoring systems for long- and short-term traffic monitoring.

When a traffic monitoring system type and accuracy level is specified by the Employer (or

when required in the previous paragraph), the Service Provider will be allowed to use one

of the alternative monitoring types listed in Table 1, but subject to the condition that the

alternative system is certified and complies with all requirements of these specification. In

the alternative, only those components may be used that are required to provide the

equivalent detection levels required for the specified monitoring system (subject to the

requirement that only components may be excluded that have been defined as optional in

the Traffic and WIM Monitoring System Certificate). The use of the alternative system is

furthermore subject to the condition that no additional payment will be made for the



- 32 -

monitoring service and that payment for the service will be made at the tariff tendered for

the specified monitoring system type.

Table 1 Alternative automatic traffic monitoring system types

Required Automatic monitoring types that may be used by Service Provider

type A1 A2 B1 B2 C1 C2 D1 D2 E1 E2

A1

A2

B1

B2

C1

C2

D1

D2

E1

E2

May be used by Service Provider subject to conditions

7.3 Traffic monitoring system size specification

In addition to the type specification provided in the previous section, the Employer must

also specify the size of the required system. The size is specified in terms of the number of

traffic lanes that must be monitored. For toll traffic monitoring systems, the number of

independent Traffic monitoring systems (two or more) must also be specified.

Except where otherwise specified by the Employer, the traffic monitoring system must be

installed over the full width of a roadway. In the case of a double carriageway road, the

monitoring system must be installed on both carriageways, even if the carriageways are

some distance apart (either as a single system or as a combination site utilising more than

one monitoring system as specified in Chapter 11 (Automatic monitoring site

requirements)).

On a road with paved shoulders, the system must be extended to include the paved

shoulders. When the shoulders are narrow, to such an extent that vehicles travelling on the

shoulder effectively form part of the traffic on the adjacent lane, the vehicles will be included

as part of the traffic in the lane. When the shoulders are wide, to the extent that it effectively

operates as a separate lane, it must be defined as a separate lane of the roadway. The

decision to define a shoulder as a lane must be agreed to by the Service Provider and the

Employer.

7.4 Detection capabilities

All traffic monitoring systems must have the following detection capabilities (Types A to E

monitoring systems):



- 33 -

a) Vehicle detection. The system must be able to detect all vehicles, other than

animal-drawn vehicles and bicycles, which are travelling on the roadway or on the

paved shoulders of the roadway and crossing the monitoring site.

b) Vehicle differentiation. The system must be able to differentiate between closely

following vehicles, but must be able to detect vehicle-trailer combinations.

c) Vehicle straddling. The system must be able to detect vehicles straddling over two

lanes of traffic and assign such a vehicle to one of the two lanes.

d) Vehicle categories (classes or types). The system must be able to detect

categories (classes or types) of vehicles as specified in these specifications. For

systems in which speeds are not recorded, an average speed for the monitoring

site may be used for the categorization (classification) of vehicles. Where the

system is capable of identifying animal-drawn vehicles and bicycles, such vehicles

must either be recorded as a separate vehicle category or discarded by the system.

Where required, the system must also have the following additional detection capabilities:

a) Speed detection (Types A, B, C and E monitoring systems). The system must be

capable of measuring the speed of each vehicle travelling over the monitoring site.

The system must also be capable of detecting whether a vehicle has stopped on

the monitoring site.

b) Axle detection (Types A, B and E monitoring systems). The system must have the

capability of detecting all axles with wheels touching the road surface. Where wheel

or axle load sensors are used for the detection of axles, the sensors must be

capable of measuring a force on the road surface equivalent to 100 kg or higher

per wheel (or 200 kg or higher per axle).

c) Single/Dual tyre detection (Type A monitoring systems). The system must be

capable of determining whether a wheel is fitted with a single tyre or with dual tyres.

7.5 Data requirements

The traffic monitoring system must be capable of recording individual vehicle data as

specified in the South African Standard Traffic Data Collection Format, including all the data

required to produce the header records defined by the format.

All monitoring systems (Types A to E) must be capable of measuring and recording the

following data for each individual vehicle passing the monitoring site:

a) Departure date and time. The departure date and time on and at which the back of

the vehicle crosses a specific point on the site (front of the vehicle when a vehicle

reverses over the site).

Dates and times must be recorded in South African Standard Time, which is the

Universal time (Greenwich Mean Time) plus 2 hours. The recording may not

change should Daylight Saving Time be introduced in the country.

The recorded dates and times may not deviate more than 30 seconds from the

Standard Time at any time.



- 34 -

Where multiple monitoring systems are used at a Combination site or at a Toll

monitoring site, the time synchronisation between the different systems may not

differ by more than 5 seconds at any time.

b) Physical lane number. The physical lane number on which a vehicle was physically

detected, irrespective of the direction in which the vehicle was travelling.

The system must be capable of recording data for up to 32 physical lanes, either

as a Single system or combined at a Combination site (as specified in Chapter 11

(Automatic monitoring site requirements)).

Types A, B, C and E monitoring systems (with speed detection) must be capable of

measuring and recording the following data for each vehicle passing the monitoring site:

a) Direction of travel (forward/reverse). The direction of travel over the site. Vehicles

normally travel in the forward direction, but vehicles may be travelling in the reverse

direction. This can occur when a vehicle reverses over the site, a vehicle is

travelling in the wrong direction or when a vehicle is overtaking another.

b) Assigned lane number (physical or virtual). The lane number to which a vehicle

travelling in the reverse direction is assigned. Provision must be made for the

following Employer-selectable options:

i) Assignment to another physical lane. This option is the default in situations

where overtaking occurs (typically on two-lane roads).

ii) Assignment to a virtual lane. A virtual lane is a lane that does not exist but

which is used to record vehicles in a reverse direction. This option is the

default for all situations other than where overtaking occurs.

iii) No assignment to any lane (vehicle is ignored).

The system must be capable of recording data for up to 32 virtual lanes in a Single

system or as a total for a Combination site (in addition to physical lanes).

c) Vehicle speed. The speed of the vehicle as recorded at a fixed position of the

vehicle (normally the front bumper or axle) and a fixed point on the site. The speed

of stopped vehicles must be recorded as zero.

The system must be capable of measuring speeds between 0 and 250 km/h.

d) Vehicle length. The length of a vehicle as measured from front to rear bumper. For

Types A to C systems, the vehicle lengths must be measured directly and for Type

E systems, the lengths may be estimated from axle spacing measurements

(subject to the accuracy requirements of this chapter).

The system must be capable of recording vehicle lengths up to 50 m.

e) Vehicle following property. The system must be able to classify a vehicle as either

following or free flowing as defined in the South African Standard Traffic Data

Collection Format. The Employer will specify the parameters (gap time and speed

differential) required for this classification.

Types A, B and E monitoring systems (with axle detection) must be capable of

measuring and recording the following data for each vehicle passing the monitoring site:

a) Number of axles. This is the number of axles on the vehicle. The system must be

able to record up to 15 axles per vehicle.



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b) Axle spacing for all axles (except first axle). The spacing between subsequent

axles. The system must be able to record axle spacing of up to 20 m.

Types A and B monitoring systems must be capable of measuring and recording the

following data for each vehicle passing the monitoring site:

a) Number of trailers. The total number of trailers towed by the vehicle. The system

must be able to record up to 15 trailers per vehicle. This measurement is not

required for Type E monitoring systems.

b) Bumper-to-1st axle spacing. The distance measured from the front bumper to the

centre of the first axle. The system must be capable of recording a spacing of up

to 10 m. In situations where the first axle is detected before the front bumper, a

negative spacing must be recorded. This measurement is not required for Type E

monitoring systems.

Type A monitoring systems (with single/dual tyre detection) must be capable of

measuring and recording whether the wheels of a vehicle have single or dual tyres.

All monitoring systems (Types A to E) must be capable of classifying and recording

vehicle categories as specified in the South African Standard Traffic Data Collection

Format. The required vehicle categories for the different monitoring system types are as

follows:

a) Types A and B monitoring systems. Vehicles must be categorised as one of the

following categories:

iii) Light vehicles (not subdivided further into the light vehicle subcategories).

iv) Heavy vehicles, subdivided into all the heavy vehicle subcategories

allowed for by the South African Standard Traffic Data Collection Format.

b) Types C to E monitoring systems. Vehicles must be classified as one of the

following two classes:

i) Light vehicles (not subdivided further into the light vehicle subcategories).

ii) Heavy vehicles (not subdivided further into the heavy vehicle

subcategories).

In situations where the system was not able to measure a particular data item, the system

must have the capability of marking or tagging such data items in such a way that allows

differentiation between missing and measured data items. Missing data items may not be

recorded as zero values (except where otherwise allowed by the South African Standard

Traffic Data Collection Format).

7.6 Resolution requirements

The traffic monitoring system must be capable of achieving the measurement resolutions

provided in Table 2. The resolutions must be smaller than or equal to those specified in

the table.

Table 2 Measurement resolutions



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Characteristic Required resolution

Departure time 0.1 second

Vehicle speed 1 km/h

Vehicle length 0.1 m

Bumper-to-1st axle spacing 0.1 m

Axle spacing 0.01 m

7.7 Detection accuracy

The vehicle, axle and single/dual tyre detection accuracy of the system is specified in terms

of tolerance limits. A tolerance limit is the maximum limit for the count of erroneous

detections, expressed as a percentage of a reference count when a very large count

representative of the population is made. The reference count is the actual count of

vehicles, axles, wheels and tyres passing the monitoring site.

Erroneous detections include the following:

a) Vehicle detection. Vehicles that were missed (not detected) or created (invented)

by the system under the following conditions:

i) Normal travel in which no straddling, lane changing, wrong direction

movements, reversing or stopping occur on the monitoring system.

ii) Vehicles straddle the system (vehicles that straddle two lanes or when lane

changing occurs).

iii) Vehicles travelling in the wrong direction or reversing over the site. This

condition will only be assessed when required by the Certification

Organisation as specified in Chapter 10 (Automatic monitoring system

assessment).

b) Trailer detection. Trailers that were missed (not detected) or created (invented) by

the system (requirements are only provided for normal travel).

c) Axle detection. Axles that were missed (not detected) or created (invented) by the

system (requirements are only provided for normal travel).

d) Wheel detection. Wheels that were missed (not detected) or created (invented) by

the system for determining whether single or dual tyres have been fitted

(requirements are only provided for normal travel).

e) Single/dual tyre classification. Incorrect classification of whether single or dual

tyres have been fitted to a wheel (requirements are only provided for normal travel).

The proportion (percentage) of erroneous detections is determined by means of the

following formula:

P = 100 ∙E

R

In which:

P = Proportion (percentage) of erroneous observations

E = Count of erroneous observations

R = Actual (reference) count

Tolerance limits are provided in Table 3 for the different types of erroneous detections.

Differentiation is made between systems that will be used for traffic and toll monitoring



- 37 -

purposes. The tolerance limits are applicable to the mixture of all vehicle categories in the

traffic stream (including motorcycles).

The tolerance limits provided in the table are applicable when a very large count

representative of the population of vehicles passing the monitoring site is made. In practice,

this is not possible and an assessment must be made by means of a random sample of

vehicles. The methodology provided for tolerance limit tests for proportions in Appendix A

must be used for such an assessment.

Table 3 Tolerance limits for invalid detection

Characteristics Travel Tolerance limits for various traffic monitoring types

A1 A2 B1 B2 C1 C2 D1 D2 E1 E2

Vehicle detection Normal travel 0.5% 1% 0.5% 1% 1% 5% 5% 10% 1% 5%

Straddling vehicles 5.0% 10% 5.0% 10% 10% 20% 20% 35% 10% 20%

Wrong dir/reversing 0.5% 1% 0.5% 1% 1% 5% 5% 10% 1% 5%

Trailer detection Normal travel 1.0% 2% 1.0% 2% - - - - - -

Axle detection Normal travel 0.5% 1% 0.5% 1% - - - - 0.5% 1%

Wheel detection Normal travel 2.5% 5% - - - - - - - -

Single/dual tyre Normal travel 0.5% 1% - - - - - - - -

7.8 Vehicle categorization (classification) accuracy

Vehicle categorization (or classification) accuracy is specified in terms of tolerance limits.

A tolerance limit is the maximum limit for the count of erroneously categorized vehicles,

expressed as a percentage of a reference count when a very large count representative of

the population is made. The reference count is the actual count of vehicles of a particular

type.

An erroneous categorization is one in which a vehicle of a particular category was either

not categorized or wrongly categorized by the system. The proportion (percentage) of

erroneous categories is determined by means of the following formula:

P = 100 ∙E

R

In which:

P = Proportion (percentage) of erroneously categorized vehicles

E = Count of erroneously categorized vehicles

R = Reference count

Tolerance limits are provided in Table 4 for the different vehicle categories. The Vehicle

categories in the table are defined in accordance with the South African Standard Traffic

Data Collection Format. The table differentiates between different detection systems, as

well as systems that will be used for traffic and toll monitoring purposes.

The assessment must exclude vehicles that:

a) Were missed or created (invented) by the system (refer to the previous section).



- 38 -

b) Straddle two lanes when passing over the monitoring site.

c) Change lanes when passing over the site.

d) Travel in a direction opposite to the normal direction of travel.

e) Reverse over the site.

f) Accelerate or decelerate while passing the site.

g) Stop on the site.

The tolerance limits provided in the table are applicable when a very large count

representative of the population of vehicles passing the monitoring site is made. In practice,

this is not possible and an assessment must be made by means of a random sample of the

vehicles. The methodology provided for tolerance limit tests for proportions in Appendix A

must be used for such an assessment.

Table 4 Tolerance limits for vehicle categorization

Vehicle category (class) Tolerance limits for various traffic monitoring types

A1 A2 B1 B2 C1 C2 D1 D2 E1 E2

Vehicles not categorised, or which were

wrongly categorised by the monitoring

system

2.0% 3.5% 3.5% 7.0% 10% 15% - - 10% 15%

Vehicles that should have been

categorised as light but which were not

categorized or categorized as heavy

1.0% 2.0% 2.0% 4.0% 6.0% 10% - - 6.0% 10%

Vehicles that should have been

categorized as heavy but which were

not categorized or categorized as light

3.0% 6.0% 6.0% 12% 20% 30% - - 20% 30%

Heavy vehicles wrongly categorized into

one of the heavy vehicle subclasses

(excluding buses)

4.0% 8.0% 8.0% 15% - - - - - -

7.9 Speed, length and axle spacing accuracy

This accuracy of the observation of vehicle speeds, lengths and axle spacing is specified

in terms of tolerance intervals. A tolerance interval is defined as one half of a zero-centred

interval in which at least a certain proportion of the population of deviations between

observed and reference values for a specific characteristic must fall. This proportion is

termed the percent-within-limits or PWL. The reference values are the values measured by

means of devices that are deemed accurate.

The deviations between observed and reference values are determined as percentages by

means of the following formula:

Di = 100 ∙Oi − Ai

Ai

In which:

i = Observation number.

Di = Deviation in measuring a given characteristic.

Oi = Observed value of the characteristic.



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Ai = Actual value of the characteristic.

The assessment must exclude those for vehicles that:

a) Straddle two lanes when passing over the monitoring site.

b) Change lanes when passing over the site.

c) Travel in a direction opposite to the normal direction of travel.

d) Reverse over the site.

e) Accelerate or decelerate while passing the site.

f) Stop on the site.

The tolerance interval is a prescribed interval (half width) in which a minimum percentage

of deviations (PWL) must fall when applied to a very large number of observations

representative of the population of all possible observations. In these specifications, a

minimum percent-within-limits (PWL) of 95% is prescribed. The required tolerance intervals

are provided in Table 5.

The speed, length and axle spacing assessments must differentiate between light and

heavy vehicles and separate assessments are required for the two vehicle categories.

Motorcycles may be excluded from the assessments (in addition to animal-drawn vehicles

and bicycles).

The range of reference values provided in the Table 5 define a lower bound of observations

that must be included in the accuracy assessment. Any observations lower than the

minimum values must be excluded from the assessments.

The tolerance intervals provided in the table are applicable when a very large number of

observations that are representative of the population of vehicles passing the monitoring

site are made. In practice, this is not possible and an assessment must be made by means

of a random sample of vehicles. The method provided for tolerance interval tests in

Appendix A must be used for this purpose.

Table 5 Tolerance intervals for vehicle speed, length and axle spacing

Characteristics Range of

reference

values

Vehicle

types (*)

Tolerance limits for various monitoring types

A1,A2,B1,B2,C1 C2 D1/D2 E1/E2

Vehicle speed -

> 30 km/h Light & Heavy 5% 10% - 5%

Vehicle length 3.0 to 5.0 m Light only 15% 30% - 30%

> 5.0 m Light & Heavy 10% 20% - 20%

Axle spacing 1.0 m to 3.0 m Light & Heavy 10% - - 10%

> 3.0 m Light & Heavy 5% - - 5%

(*) Excluding motorcycles, bicycles and animal drawn vehicles



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8 HS WIM MONITORING SYSTEM REQUIREMENTS

8.1 HS WIM requirements

This chapter provides the requirements for High-Speed WIM Monitoring Systems. Such

systems may be provided as a stand-alone system or must be integrated with a Traffic

Monitoring System to provide an integrated Traffic and HS WIM Monitoring service.

The requirements of this chapter are in addition to the requirements provided in Chapter 6

(General automatic monitoring system requirements) and Chapter 7 (Automatic traffic


8.2 Static and dynamic loads

Loads measured by means of HS WIM systems consist of two components, namely the

static and dynamic load components. Engineering applications of axle loads, however, only

require estimates of the static load component rather than the actual impact forces as

measured by WIM sensors. The reasons for this requirement are as follows:

a) The technical analysis (or design) procedures that are used for the engineering

design of pavements are based on static axle loads. The dynamic load component

depends on the condition of the road pavement, and can thus be expected to

change in future as the road deteriorates or when the road is rehabilitated. The

design procedures must therefore make an estimation of the dynamic loads as a

function of the condition of the road and add this component back to the static load.

b) The screening of vehicles at weighbridges should be based on static axle loads

since vehicles are stationary when weighed at a weighbridge.

Many of the requirements of these specifications are aimed at minimising the effect of the

dynamic load component with the purpose of improving the accuracy with which static axle

loads can be estimated. However, it is not possible to fully eliminate dynamic loads and

statistical methods are thus used to remove the effect from the observations.

8.3 HS WIM Monitoring system types

When specifying a HS WIM monitoring system, the Employer must specify the following:

a) Whether a stand-alone system is required or whether it must be integrated with a

traffic monitoring system. Where the system will be used for screening purposes,

the required screening facilities must be specified.

b) Where required, the type of traffic monitoring system that must be integrated with

the HS WIM system (types as defined in Chapter 7 (Automatic traffic monitoring

system requirements)). Types A2 and B2 traffic monitoring systems are generally

recommended for this purpose (but only for the lanes in which the HS WIM

monitoring is undertaken).



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In the absence of a traffic monitoring type specification by the Employer, Type B2 traffic

monitoring systems must be used in lanes in which HS WIM monitoring are undertaken.

8.4 HS WIM Monitoring system sizes

When specifying a HS WIM monitoring system, the Employer must specify the lanes on

which HS WIM monitoring must be undertaken. In the absence of such a specification, HS

WIM monitoring must only be undertaken on the left-most lanes in each direction of travel

at the site. Where the HS WIM in integrated with a traffic monitoring system, the traffic

monitoring must be undertaken over all lanes of the road.

8.5 Accuracy levels

The Employer must also specify the required HS WIM accuracy level. Differentiation must

be made between the following accuracy levels:

a) Class I - Relatively high level of accuracy. This level of accuracy is recommended

for use on very smooth road surfaces where dynamic effects will be low. This class

should be used when it critical to achieve a relatively high level of accuracy.

b) Class II - Higher level of accuracy. This level of accuracy is recommended for roads

that carry medium to high volumes of heavy vehicle traffic and where a higher level

of accuracy is required.

c) Class III - Lower level of accuracy. This level of accuracy is recommended for roads

that carry low volumes of heavy vehicle traffic and where a lower level of accuracy

is acceptable.

In the absence of an accuracy level specification by the Employer, a HS WIM system with

a Class II accuracy level must be provided.

8.6 Detection capabilities

The HS WIM system must have the following detection and measurement capabilities:

a) Axle load measurement. The system must be capable of measuring and recording

axle loads of individual axles of a vehicle. Such measurement may be undertaken

by either wheel or axle sensors and at least one such sensor must be installed on

each lane that is monitored. Where wheel load sensors are used, the axle load

must be recorded as double (twice) the wheel load.

b) Axle spacing measurement. The load sensors must also be capable of measuring

and recording axle spacing.

c) Off-scale detection. The system must be capable of detecting wheels that did not

fully pass over but only clipped the wheel or axle load sensors. Sufficient sensors

must be provided to ensure that all wheels clipping the load sensors are detected.



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8.7 Screening requirements

Where screening facilities are specified for a HS WIM monitoring system at a weighbridge,

an electronic communication facility must be provided which is capable of passing all the

information collected for individual vehicles to another computer or control system. The

requirements for the communication facility will be specified by the Employer.


The HS WIM system must be capable of recording individual vehicle data as specified in

the South African Standard Traffic Data Collection Format, including all the header records

required for the recording of such data. In addition to the data specified in Chapter 7

(Automatic traffic monitoring system requirements), the system must measure, collect and

record the following data for each vehicle passing the monitoring site:

a) Number of axles. This is the number of axles for which axle loads were recorded.

The system must be able to record axle spacing and wheel or axle loads for up to

15 axles per vehicle.

b) Load measurement resolution. The load resolution with which the axle loads on the

vehicle were measured. This resolution may change from vehicle to vehicle, but

not from axle to axle on the same vehicle.

c) Axle spacing. The spacing between subsequent axles as measured by the wheel

or axle load sensors. The system must be able to record an axle spacing of up

to 20 m.

d) Axle loads. The loads for each axle as measured by a wheel or axle load sensor.

Where wheel load sensors are used, the axle load must be recorded as double

(twice) the wheel load. Where separate axle sensors are used, wheel load sensors

must be capable of measuring wheel loads between 250 and 10 000 kg and axle

load sensors must be capable of measuring axle loads between 500 and 20 000

kg. Where separate axle sensors are not used, wheel load sensors must be

capable of measuring wheel loads between 100 and 10 000 kg and axle load

sensors must be capable of measuring axle loads between 200 and 20 000 kg.

The system must be capable of measuring the loads for vehicles travelling at

speeds higher than 15 km/h up to a speed of 140 km/h.

e) Load sensor clipping. The system must indicate whether the load sensor was

clipped by any of the wheels of the vehicle. Such clipping must be detected by

means of off-scale sensors.

In a situation where the system is not able to measure a data item, the system must use

marks or tags to allow identification of invalid data items. Invalid data items may not be

tagged or marked by means of zero values.

Vehicle, axle or wheel loads may NOT be used as a criterion in the vehicle classification

systems described in Chapter 7 (Automatic traffic monitoring system requirements) of these

specifications.



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8.9 HS WIM Sensor step requirements

Where a HS WIM sensor is mounted on the surface of the road pavement, the height of the

step between the top of the HS WIM sensor and the adjacent road surface may not exceed

2 mm at any location along the up- and downstream edges of the sensor.

The height of the step must be measured by means of a 2 mm thick 150 mm diameter

circular plate and a straight edge.


The HS WIM system must be capable of achieving the measurement resolutions provided

in Table 6. The resolutions must be smaller or equal to those specified in the table.

Table 6 HS-WIM Load and spacing resolutions


Load measurements 10 kg

Axle-spacing measurement 0.01 m

8.11 Axle detection and axle spacing accuracy

The axle detection and axle spacing measurements by means of the load sensors must

comply with the requirements of Chapter 7 (Automatic traffic monitoring system

requirements).

8.12 Load accuracy

The accuracy of load measurements made by HS WIM systems is specified in terms of

tolerance intervals. A tolerance interval is defined as one half of a zero-centred interval in

which at least a certain proportion of the population of deviations between observed and

reference loads must fall. This proportion is termed the percent-within-limits or PWL.

For the purposes of these specifications, three reference loads must be used, namely

a) gross vehicle loads (mass), b) axle group loads for axle groups with more than one axle

and c) axle loads for axle groups with one axle.

The test vehicles used for the accuracy assessment must be selected randomly from the

traffic stream. The reference loads for the test vehicles must be obtained from a static

weighbridge but if a weighbridge is not available, the reference loads may be obtained from

a certified LS WIM system.

In order to reduce the effect of dynamic loads on the evaluation, a test site should be

selected that complies with the roadway and desirable pavement requirements of Chapter

11 (Automatic monitoring site requirements). Loads measured at wind speeds of greater

than 30 km/h may also be excluded from the assessment (optional).



- 44 -

The deviations between the observed loads and the reference loads are determined in

percentages by means of the following formula:

Di = 100 ∙Oi − Ri

Ri

In which:


Di = Deviation in load measurement.

Oi = Observed load (WIM measurement).

Ri = Reference load.

The observed loads are those measured by the HS WIM system. The observed loads shall

NOT be used for calibrating the system.

In HS WIM systems where wheel load sensors are used and where reference loads are

available for the different wheels on the axle (from either the weighbridge or the LS WIM),

the observed axle load shall be estimated by means of the following formula:

Observed axle load =Reference axle load

Reference wheel load∙ Observed wheel load

Where reference wheel loads are not available, the observed axle load shall be estimated

as double the observed wheel load.

The tolerance interval is a prescribed interval within which a minimum percentage of

deviations must fall when applied to a very large number of observations representative of

the population of all possible observations. In these specifications, a minimum percent-

within-limits (PWL) of 95% is required. The required tolerance intervals are given in Table 7

for the three reference loads.

The minimum values provided in the table define a lower limit for observations that must

be included in the accuracy assessment. Any observations lower than the minimum values

must be excluded from the assessment.

The assessment must also exclude vehicles that:

a) Straddle two lanes when passing over the monitoring site.

b) Change lanes when passing over the site.

c) Travel in a direction opposite to the normal direction of travel.

d) Reverse over the site.

e) Accelerate or decelerate while passing the site.

f) Stop on the site.

g) Crosses the site when the wind speed exceeds 30 km/h (optional).

Table 7 differentiates between the different accuracy classes I to III.


observations that are representative of the population of vehicles passing the monitoring

site are made (including repeated passes of the test truck over the site). In practice, this is

not possible and an assessment must be made by means of a random sample of vehicles.

The method provided for tolerance interval tests in Appendix A must be used for this

purpose.



- 45 -

Table 7 HS WIM Tolerance intervals for load measurements

Load

Minimum

Value Tested

Tolerance intervals for different accuracy classes

Class I Class II Class III

Gross vehicle mass 3 500 kg per

axle

8% 10% 15%

Axle group load (*1) 12% 15% 20%

Single axle load (*2) 12% 15% 25%

*1 Excluding groups with one axle

*2 Single axles in single axle groups

8.13 Calibration of HS WIM systems

No procedure is prescribed in these specifications for the calibration of a HS WIM system

and the calibration procedure prescribed by the System Supplier must be implemented.

Although no calibration procedure is prescribed in these specifications, a calibration

process is described in Chapter 19 (Monitoring data requirements) based on load

measurements by a HS WIM system. This process includes a requirement that the

calibration factor produced by the process must fall in the range 0.90 to 1.10. Should the

factor fall outside this range, the HS WIM system must be recalibrated to comply with this

requirement.



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9 LS WIM MONITORING SYSTEM REQUIREMENTS

9.1 LS WIM requirements

This chapter provides requirements for monitoring systems that must be used for the

provision of Low-Speed (LS) WIM Monitoring services. These requirements are in addition

to the general requirements provided in Chapter 6 (General automatic monitoring system

requirements) but not the requirements for traffic monitoring systems provided in Chapter

7 (Automatic traffic monitoring system requirements).

LS WIM monitoring systems are used to measure left and right wheel loads of vehicles

travelling at low speeds (lower than 10 km/h) to allow direct observations of static loads.

The systems are used for purposes such as axle load observations as well as the

calibration and validation of HS WIM systems.

9.2 System size specification

When specifying a LS WIM monitoring system, the Employer must also specify the required

size of the system. The size is specified in terms of the number of systems that must be

operated at one site. Where the LS WIM is installed on the roadway, a separate system will

be required for each lane to be monitored.

9.3 Operational requirements

The LS WIM system must comply with the following requirements:

a) The system must be able to operate under manual control.

b) The system must be portable and the system must be easily moved between

monitoring sites.

c) The system must be equipped with both left and right wheel load sensors.

When loads are being measured, the vehicle drivers must be requested to fully release all

brakes on the vehicle.


The LS WIM system must be able to measure, collect and record the following data for

each vehicle:

a) Number of axles. This is the number of axles for which loads were recorded. The

system must be able to record axle loads for up to 15 axles per vehicle.



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b) Left and right wheel loads for all axles. The wheel loads for each axle as measured

by a wheel load sensor. The system must be capable of measuring wheel loads

between 250 and 10 000 kg for vehicles travelling at speeds lower than 10 km/h.


The LS WIM system must be capable of achieving the measurement resolution provided in

Table 8. The resolution must be smaller or equal to that specified in the table.

Table 8 LS WIM Axle load measurement resolution


Load measurements 10 kg

9.6 Load accuracy

The accuracy of load measurements made by a LS WIM system is specified in terms of

tolerance intervals. A tolerance interval is defined as one half of a zero-centred interval in

which at least a certain proportion of the population of deviations between observed and

reference loads must fall. This proportion is termed the percent-within-limits or PWL.

For the purposes of these specifications, the observed load at a LS WIM is taken as the

sum of the left and right wheel loads while the reference load is taken as the static axle

load measured at a static weighbridge. Gross vehicle mass and axle group loads are not

used in the assessment.

The deviations between observed and reference axle loads are determined as percentages

by means of the following formula:

Di = 100 ∙Oi − Ri

Ri

In which:


Di = Deviation in load measurement.

Oi = Observe sum of wheel loads (LS WIM measurement).

Ri = Reference axle load.

The tolerance interval is a prescribed interval in which a minimum percentage of deviations

must fall when applied to a very large number of observations, representative of the

population of all possible observations. In these specifications, a minimum percent-within-

limits (PWL) of 95% is required. The required tolerance intervals for the deviations are given

in Table 9.

The minimum values provided in the table define a lower limit for observations that must

be included in the accuracy assessment. Any observations lower than the minimum values

must be excluded from the assessment.


observations, representative of the population of vehicles passing the monitoring site are



- 48 -

made (including repeated passes of the test truck over the site). In practice, this is not

possible and an assessment must be made by means of a random sample of vehicles or

passes of the test truck. The method provided for tolerance interval tests in Appendix A

must be used for this purpose.

Table 9 LS WIM Tolerance limits for load measurements

Load Minimum value Tolerance interval

Axle load 1 250 kg 5%



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10 AUTOMATIC MONITORING SYSTEM ASSESSMENT

10.1 System assessments

The issuing of a Traffic and WIM Monitoring System Certificate by the Certification

Organisation to a System Supplier for a monitoring system is subject to the condition that

one installation of the monitoring system is assessed and found to comply with the

requirements of this chapter in addition to the requirements of the following chapters of

these specifications:

• Chapter 3 (Traffic and WIM Monitoring System Supplier quality assurance).





10.2 Monitoring system assessment reviews

A full monitoring system assessment, as specified in this chapter, will be undertaken when

an application is made for a new Traffic and WIM Monitoring System Certificate. For the

review of the monitoring systems as required in Chapter 3 (Traffic and WIM Monitoring

System Supplier quality assurance), however, the Certification Organisation may only

require a partial assessment of the system.

The review must, at a minimum, include assessments of the following requirements as

specified in this chapter:

a) Evidentiary documentation.

b) Visual inspection assessments.

The requirements below will be assessed when an application is made for a new certificate.

During the review of the monitoring system, the Certification Organisation will decide on

whether these assessments must be undertaken.

a) Operational assessments.

b) Accuracy assessments.

c) Data assessments.

10.3 Monitoring system assessment

The Systems Supplier will be responsible for undertaking the assessments required by

these specifications, but such assessments must be undertaken under control and

supervision of the Certification Organisation. The System Supplier will inter alia be

responsible for the following:



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a) Selection and preparation of the site and the installation of a monitoring system at

which the assessment will be undertaken.

b) Provision of all testing equipment and facilities that are required for the

assessment.

c) Undertaking all required tests and the collection and analysis of test data.

d) Submission of the information and collected data, as well as the results of the

assessment to the Certification Organisation.

The Certification Organisation will verify that the assessments have been undertaken in

accordance with the specifications, and that the assessments have not been falsified or

fabricated. For this purpose, it will not be necessary to verify all the data collected during

the assessments and a sample of data may be randomly or specifically selected for this

purpose. The Certification Organisation will also verify that collected data were analysed

correctly and that the system complies with the accuracy and other requirements of these

specifications.

10.4 Monitoring system components

The monitoring system installation for the assessment must include all the components,

including those that are considered as optional. Where a monitoring system consists of

optional components, assessments must also be undertaken to determine whether the

operation and accuracy of the system will not be affected by excluding the optional

components.

10.5 Assessment site

The System Supplier will be responsible for the selection and preparation of the

assessment site. The system may be assessed at a new site or at an existing site that

complies with the roadway and desirable pavement requirements specified in Chapter 11

(Automatic monitoring site requirements).

The traffic monitoring system must be installed over all lanes at the site (and shoulders

were appropriate). On multilane roads, however, the installation is only required for one of

the travel directions, provided that the system is installed over at least two lanes in the

direction. WIM monitoring systems must be assessed in combination with a traffic

monitoring system but the WIM assessment is only required for one of the lanes at the site.

Where assessments of load accuracies are required, the following additional requirements

apply:

a) The site should preferably be near to a static weighbridge that can be used to

undertake the reference load measurements.

b) Where a weighbridge is not available, a certified LS WIM may be used to undertake

the load measurements. A suitable location must then be available at which a LS

WIM system can be installed. Preference should be given to the installation of the

LS WIM on the roadway itself or on the paved shoulder, but a constructed lay-by

may also be used for this purpose. The LS WIM site must be at least 1 km

downstream or at least 5 km upstream of the assessment site to prevent the

possible interference of traffic flow at the assessment site.



- 51 -

Approval must be obtained from the Road Authority responsible for the road on which the

monitoring system assessment will be undertaken. The System Supplier will also be

responsible for restoring the site to the satisfaction of the Road Authority responsible for

the road on completion of the assessment.

10.6 Assessment duration

The monitoring system assessment must be undertaken over the following durations:

a) Assessments required for new certificates. The duration of the monitoring

assessment required for new certificates are as follows:

i) 28 Days for monitoring systems that will be used for traffic monitoring over

periods of longer than 7 days.

ii) 14 Days for monitoring that will only be used for traffic monitoring over

periods of 7 days or shorter.

b) Reviews of monitoring systems. During reviews the duration of the assessment

must be the minimum required to complete all the assessments required for the

review.

During the assessment, a total of 24 hours of grace will be allowed during which the System

Supplier may undertake adjustments or repair the equipment, provided that the make, type

or version of the equipment is not changed. Failure to comply with this requirement will be

taken as failure of the system.

Some of the assessments may require interference with the operation of the system, but

where possible, the assessments must be undertaken without affecting operations.

Data must continuously be collected over the duration of the assessment. Data must be

available for the full assessment period, excluding the grace period and the periods during

which the monitoring system assessments have interfered with the operation of the system.

Failure in providing the full data set will be taken as failure of the system.

10.7 Evidentiary documentation

The System Supplier must submit the evidentiary documentation listed below to the

Certification Organisation to show that the system complies with the following

requirements. The Certification Organisation will assess the documentation to determine

whether the system and document complies with the requirements of these specifications.

a) The following manuals as specified in Chapter 3 (Traffic and WIM Monitoring

System Supplier quality assurance):

i) System supplier quality assurance manuals.

ii) Service provider quality assurance manuals.

iii) Service provider training manuals.

iv) Service provider monitoring system manuals.

b) The following general requirements as specified in Chapter 6 (General automatic

monitoring system requirements):



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i) Environmental conditions.

ii) Environmental requirements.

iii) Operational requirements.

iv) Power provision requirements.

v) Data recording capabilities.

vi) Data extraction requirements.

vii) Real-time monitoring requirements.

c) The following traffic monitoring system requirements as specified in Chapter 7

(Automatic traffic monitoring system requirements):

i) Detection capability requirements.

ii) Data requirements.

iii) Resolution requirements.

The evidentiary documentation must include evidence that shows that the system

is capable of detecting and recording the directions of vehicles travelling in the

wrong direction or which are reversing over the monitoring site. Where such

evidence are not acceptable to the Certification Organisation, the Service Provider

will be allowed to undertake an assessment at a site at which the monitoring system

is installed in the reverse direction (opposite to the normal direction of travel). In

such case, the detection accuracy requirements of Chapter 7 (Automatic traffic

monitoring system requirements) will apply.

d) The following high-speed WIM system requirements as specified in Chapter 8

(Traffic and HS WIM monitoring system requirements):

i) Detection capability requirements.

ii) Data requirements.

iii) Resolution requirements.

e) The following low-speed WIM system requirements as specified in Chapter 9 (LS

WIM Monitoring system requirements):

i) Data requirements.

ii) Resolution requirements.

10.8 Visual inspection assessment

A visual inspection of the installed monitoring system will be undertaken by the Certification

Organisation, with the assistance of the System Supplier, with the purpose of evaluating

the following general requirements as specified in Chapter 6 (General automatic monitoring

system requirements):

a) Whether the installed system and sensors have not caused, or will not cause,

undesirable environmental effects.

b) Whether the installed system and sensors are not aesthetically or

visually obtrusive.

c) Whether the system is reasonably protected against theft and vandalism.

d) Whether the sensors remain fixed for the duration of the assessment and the

likelihood that the sensors will remain fixed in future.



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e) Whether the system or sensors may create a road or traffic hazard or endanger

the safety of people, animals, vehicles or property.

10.9 Operational assessment

Operational assessments of the installed system must be undertaken by the Certification

Organisation, with the assistance of the System Supplier, to determine whether the system

complies with the following general requirements as specified in Chapter 6 (General

automatic monitoring system requirements):

a) Whether recorded data will be lost when power supply to the system is interrupted

or switched off.

b) Whether the system allows data extraction while in operation, and without affecting

the data collection and processing capabilities of the system.

c) Whether the system has the specified real-time monitoring capabilities.

10.10 Accuracy assessment

The following accuracy assessments must be undertaken by the System Supplier under

the control and supervision of the Certification Organisation, with the purpose of evaluating

whether the system complies with the accuracy requirements of these specifications:

a) Vehicle, trailer, axle, wheel and single/dual tyre detection and vehicle classification

accuracy requirements as specified in Chapter 7 (Automatic traffic monitoring

system requirements).

b) Speed, vehicle length and axle spacing accuracy requirements as specified in

Chapter 7 (Automatic traffic monitoring system requirements).

c) High-speed WIM load accuracy requirements as specified in Chapter 8 (Traffic and

HS WIM monitoring system requirements).

d) Low-speed WIM load accuracy requirements as specified in Chapter 9 (LS WIM

Monitoring system requirements).

The methodology that must be followed for the assessment of the accuracy of a monitoring

system is described in Appendix C. This methodology requires that the System Supplier

must undertake all the required assessments while the Certification Organisation only

needs to verify the assessments on a sampling basis. The purpose of such verification is

to ensure that the assessments have been correctly undertaken and that the assessments

have not been falsified or fabricated.

The minimum sample size requirements for the accuracy assessments by the System

Supplier are given in Table 10. Differentiation is made in the table between the different

accuracy requirements as well as the different monitoring system types and classes. The

minimum sample sizes are applicable to vehicles that comply with the different

requirements of the accuracy specifications (including any range or minimum value

requirements).

The System Supplier may increase any of the minimum sample sizes in Table 10 to improve

the statistical reliability of the assessment. No vehicles, however, may be excluded from

the sample when the sample size is increased.



- 54 -

The sample sizes required by the Certification Organisation for the verification of the

assessments will be determined by the organisation.

Table 10 Minimum sample size requirements for monitoring system assessments

Traffic monitoring requirements Traffic monitoring system type

A1 A2 B1 B2 C1 C2 D1 D2 E1 E2

Vehicle detection - Normal travel 600 300 600 300 300 60 60 30 300 60

Vehicle detection - Straddling veh 60 30 60 30 30 30 30 30 30 30

Vehicle detection – Wrong direction 600 300 600 300 300 60 60 30 300 60

Trailer detection 300 150 300 150 - - - - - -

Axle detection 600 300 600 300 - - - - 600 300

Wheel detection 120 60 - - - - - - - -

Single/dual tyre 600 300 - - - - - - - -

Vehicles not/wrongly categorised 300 150 150 75 50 30 - - 50 30

Light vehicles categorised as heavy 300 150 150 75 50 30 - - 50 30

Heavy vehicles categorised as light 300 150 150 75 50 30 - - 50 30

Heavy vehicles wrongly categorised 300 150 150 75 50 30 - - 50 30

Light vehicle speed > 30 km/h 100 100 100 100 100 100 - 100 100

Heavy vehicle speed > 30 km/h 100 100 100 100 100 100 - 100 100

Light vehicle length 3 to 5 m 100 100 100 100 100 100 - - 100 100

Light vehicle length > 5 m 100 100 100 100 100 100 - - 100 100

Heavy vehicle length > 5 m 100 100 100 100 100 100 - - 100 100

Light vehicle axle spacing 1 to 3 m 100 100 100 100 - - - - 100 100

Light vehicle axle spacing > 3 m 100 100 100 100 - - - - 100 100

Heavy vehicle axle spacing 1 to 3 m 100 100 100 100 - - - - 100 100

Heavy vehicle axle spacing > 3 m 100 100 100 100 - - - - 100 100

HS WIM monitoring requirements HS WIM monitoring system class

Class I Class II Class II

Gross vehicle mass 200 200 200

Axle group mass (excl single axles) 200 200 200

Single axle load 200 200 200



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10.11 Data assessment

The System Supplier will be required to extract data on a daily basis and submit the data

to the Certification Organisation in accordance with the requirements specified in Chapter

19 (Monitoring data requirements). The data must be converted to the format as specified

in the South African Standard Traffic Data Collection Format and authenticated by means

of authentication software to be provided by the South African National Road Agency Ltd

(SANRAL).

The submitted data must be verified and analysed by the System Supplier in accordance

with the requirements of and using the data management software of the South African

National Road Agency Ltd (SANRAL) as specified in Chapter 19 (Monitoring data

requirements). The requirements include those applicable to the time periods in which the

verification must be completed. The results of the verification and analysis must be made

available to the Certification Organisation.

If any of the data are found suspect, then the data must be investigated by the System

Supplier and recommendations made to the Certification Organisation on whether the data

must be accepted or rejected in terms of the requirements specified in Chapter 19

(Monitoring data requirements). The Certification Organisation may accept or reject such

recommendations. If rejected, the system will be considered to have failed.

Part 3: Automatic Monitoring Site and System Installation Requirements


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Part 3

Automatic Monitoring Site

and System Installation

Requirements



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Part 3: Automatic Monitoring Site and System

Installation Requirements

Part 3 contains the requirements that are applicable to monitoring sites and system

installations where traffic monitoring and WIM services are provided. These requirements

are applicable to the provision of automatic traffic and WIM monitoring services and not to

manual traffic monitoring services. The requirements are provided in the following chapters:

Chapter 11 Automatic monitoring site requirements.

Chapter 12 Installed automatic monitoring system requirements.

Chapter 13 Installed automatic monitoring system assessments.

Chapter 14 Site works requirements.



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11 AUTOMATIC MONITORING SITE REQUIREMENTS

11.1 Site requirements

This chapter provides requirements that must be complied with in locating monitoring sites

at which monitoring systems will be installed for the provision of monitoring services.

The requirements of this chapter are not only applicable at the commencement of a

monitoring service but must be complied with for the full duration of the service.

11.2 Monitoring site definition

A monitoring site is a single location where all the lanes of traffic are monitored as specified

by the Employer. The site must include all the roadways and lanes on the site (up to a

maximum of 32 lanes per site). On double carriageway roads, both carriageways are

included, even if such carriageways are located some distance apart. Where monitoring is

undertaken at an intersection or interchange, all the roadways at the intersection or

interchange must be included as part of the site (unless specified otherwise by the

Employer).

In situations where a Service Provider may require multiple monitoring systems to monitor

all the roadways and lanes as a single site, the Service Provider may define partial sites

and combine these sites in a Combination site as specified in the South African Standard

Traffic Data Collection Format. For the purpose of these specifications, such a combination

site is treated as a single site. The Employer may, however, specify that the collected data

must be submitted for each individual partial site or for the combination site as a whole.

Where toll monitoring is undertaken, each individual toll monitoring system must be defined

as a separate monitoring site and not as a combination site. Each individual monitoring

system must operate fully independently of each other.

11.3 Monitoring site stratification

Short-term (shorter than one year) traffic characteristics must be expanded to equivalent

annual characteristics using expansion factors derived by means of a stratification system.

The stratification systems (one or more) that must be used for this purpose is defined in

TMH 8 (COTO, 2015).

The system requires that both short-term and long-term monitoring sites must be grouped

into stratification strata and clusters consisting of one or more monitoring sites with similar

characteristics. Each stratum must contain at least one long-term monitoring site. For each

stratum or cluster, a set of expansion factors and typical traffic characteristics must be

derived from the long-term sites that can be used for deriving equivalent annual

characteristics at the short-term sites.



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The Service Provider in co-operation with the Employer will be responsible for implementing

the stratification system, including the grouping of monitoring sites in strata and clusters

(unless otherwise specified by the Employer). The Employer will specify the software that

must be used by the Service Provider for this purpose. In the absence of such specification,

the software specified by the South African National Road Agency Ltd (SANRAL) shall be

used for this purpose.

11.4 Monitoring site location

The Employer will specify a road section on which traffic and/or WIM monitoring must be

undertaken, but the Service Provider is responsible for selecting the exact location of the

monitoring site. The Service Provider is responsible for ensuring that the roadway at the

site complies with the requirements specified in this chapter.

The Employer or Road Authority may make information available that can be used by the

Service Provider for the selection of the location of the monitoring site. The Service Provider

will, however, be responsible for ensuring that the provided data is correct and that the

selected location fully complies with the requirements specified in this chapter.

In the selection of the site, consideration must be given to the probability that the roadway

may deteriorate to such an extent that it may not comply with the requirements specified in

this chapter during the required period of observations. Should a monitoring site be

discontinued during monitoring, the requirements specified in Chapter 21 (Payment

requirements) of these specifications will apply.

11.5 Existing monitoring sites

Where an existing monitoring site is available on a road section, preference must be given

to the re-use of such a site. The Service Provider must therefore investigate the suitability

of such a site in terms of the following requirements:

• It must be possible to install the monitoring system at the site (the site must be

compatible with the requirements of the monitoring system).

• The site must fully comply with the requirements specified in this chapter and

continue to do so for the duration of the monitoring service.

Where an existing monitoring site is found to be unsuitable, the Service Provider must

submit a report to the Employer stating the reasons why the site is unsuitable for re-use.

Where a site is found to be suitable, the facilities that were previously installed at the site

must be re-used as far as possible.

11.6 Road geometry and pavement requirements

Requirements for the geometry of a road and the quality of the road pavement are provided

in the following sections of this chapter. No monitoring may be undertaken at sites that do

not comply with these requirements, unless otherwise required by the Employer.



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The Employer may require monitoring on road sections that do not comply with the

requirements. In such cases, the Service Provider must select the best available sites on

the road sections. However, none of the accuracy requirements affected by such non-

compliance will then be applicable to the monitoring site and the Service Provider will not

be penalised for such non-compliance.

The following accuracy requirements may be affected by the non-compliance:

a) Accuracy requirements for toll and traffic monitoring provided in Chapter 7

(Automatic traffic monitoring system requirements).

b) Accuracy requirements for HS WIM monitoring provided in Chapter 8 (HS WIM


c) Data verification tests provided in Appendix D.

11.7 Road geometry requirements

The road geometry requirements provided in this section are applicable to monitoring sites

where toll, traffic or HS WIM monitoring will be undertaken, but not to LS WIM monitoring.

The following road geometry requirements are applicable to all toll, traffic and HS WIM

monitoring sites:

a) The site must not be located at a position where the accuracy of the monitoring can

be affected by factors such as the following:

i) Acceleration and deceleration caused by any permanent or temporary

obstructions on the road. Such acceleration may occur near to

intersections interchanges, railway crossings, toll plazas, truck stops,

steep gradients, sharp curves, no-overtaking lines or any other

obstructions that may result in speed changes along the road.

ii) Stopping on the site or on the shoulder (including queue formation at a

downstream location).

iii) Lane changing and straddling due to factors such as overtaking, weaving,

vehicles travelling or stopping on the shoulders. Where no suitable site can

be identified, the Employer may consider the installation of traffic

channelling devices.

b) The monitoring site must not be located close to a radio transmitter, under a high

voltage power line, close to a railway track or anything else which could affect the

operation of the monitoring system.

A further requirement applicable to HS WIM monitoring sites only (not to traffic and toll

monitoring sites) is that the sites must not be located at positions where load transfer can

occur between different axles or wheels of a vehicle. The following requirements, in addition

to those listed above, are required for this purpose:

a) The road segment between 200 m upstream and 50 m downstream from the HS

WIM site must comply with the following requirements:

i) The longitudinal gradient (slope) must preferably not be steeper than 1%

but gradients of up to 2% are acceptable.

ii) The transverse slope (crossfall) must preferably be less than 2% but

slopes of up to 3% are acceptable.



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iii) The horizontal curve radius must preferably not be greater than 2 500 m

but radii of down to 1 000 m are acceptable.

iv) There must be no changes in road width (including shoulder width) that

could result in lane change manoeuvres at the site.

b) The site must be located away from the following:

i) A bridge overpass that could result in aerodynamic effects on vehicles.

ii) Any structure giving support different from that of the road pavement.

The Service Provider is responsible for obtaining the information required for the

assessment of the above road geometry requirements. Where such information is not

available, the Service Provider must undertake the measurements required for

the assessment.

11.8 Road pavement requirements

The road pavement requirements provided in this section are only applicable to sites where

HS WIM monitoring will be undertaken. The requirements are aimed at ensuring a relatively

smooth road surface with a low level of flexibility that is required for accurate and reliable

HS WIM monitoring.

The pavement of the road segment between 200 m upstream and 50 m downstream of the

site must comply with the requirements provided in Table 11 with respect to the following

pavement properties:

a) Rutting (mm)

i) Measured in accordance with the requirements of TMH13 Automated

Pavement Condition Measurements (COTO, 2013).

ii) Measured at 10 m intervals (measured with a 2 m straight edge).

Measured over the wheel path in which the HS WIM sensor is installed.

iii) The highest observation may not exceed the worst value given in the table.

iv) The 95th percentile observation may not exceed the allowable value in the

table.

b) International Roughness Index IRI (mm/m)


Pavement Condition Measurements (COTO, 2013).

ii) Measured at 10 m intervals in both wheel paths.



table.

c) Maximum Deflection (m)


Pavement Condition Measurements (COTO, 2013). An axle load of

8000 kg (80 kN) must be used for this purpose.

ii) Measured at 5 m intervals in the wheel path in which the WIM sensor is

installed.




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table.

d) Faulting (mm), in the case of jointed concrete pavements

i) Measured in accordance with the requirements of TMH9 Visual

Assessment Manual for Roads (COTO, 2013).

ii) A minimum of 10 observations of joints near to WIM sensor.


iv) The average of the observations may not exceed the allowable value in

the table.

e) Visual assessment of structural defects (cracking, pumping, showing)

i) Determined in accordance with the requirements of TMH9 Visual

Assessment Manual for Roads (COTO, 2013).

The worst and allowable values provided in Table 111 must be complied with. New

monitoring sites should preferably be installed at locations that comply with the desirable

values to allow for the possible deterioration of the pavement over time.

Table 11 Pavement criteria applicable to concrete and asphalt pavements

Requirement Worst observation Allowable value Desirable value

Rutting, mm 12.0 7.0 4.0

IRI, m/km 3.0 2.6 1.6

Max Deflection, m 600 400 250

Faulting, mm 5.0 3.0 2.0

Visual assessment No cracking, pumping or shoving of Degree 2 or higher

The Employer will specify whether the measurements and assessments required for

assessing the above road pavement requirements must be undertaken by the Service

Provider. In the absence of such specifications, the Service Provider will be required to

undertake the measurements and assessments. When required, such measurements and

assessments will be paid for in terms of the pay items provided in Chapter 20 (Monitoring

service specification).

11.9 LS WIM Sites

The following geometric requirements are applicable to sites where LS WIM monitoring will

be undertaken:

a) The longitudinal gradient may not exceed the following:

i) A maximum of 0.1% over a distance of 2 m up- and downstream of the LS

WIM sensors.

ii) A maximum of 0.5% over a distance of 25 m up- and downstream of the

LS WIM sensors.



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b) The crossfall over a distance of 25 m up- and downstream of the LS WIM sensors

may not exceed a preferable maximum of 2% but a crossfall of up to 3%

is acceptable.

11.10 Power provision requirements

The Service Provider is responsible for procuring the power supply required to operate the

system, irrespective of where the monitoring is to be undertaken. Any power source suitable

to operate the system may be used, such as electrical power, solar panels, batteries or any

other suitable power system. The availability of power supply may be an important

consideration in the selection of a monitoring site.

11.11 Traffic channelling devices

The Employer may consider the installation of traffic channelling devices in situations where

it is not possible to identify a site where unwanted movements do not occur. Unwanted

movements include movements such lane changing, weaving, straddling or vehicles

travelling or stopping on the shoulder which would affect the accuracy of the traffic

monitoring. Devices such as guardrails, rumble strips, road signs or road markings may be

used for this purpose.

The Service Provider is responsible for making recommendations on the most suitable

channelling devices. The Employer may decide to implement the devices, reject the site or

continue with the monitoring without such devices. The Employer will be responsible for the

installation of such traffic channelling devices.

11.12 Obstructions and services

The site may not be located near to any obstruction or services where it will be necessary

to protect, move or relocate the obstruction or services. Where the site cannot be located

elsewhere, the site must be referred to the Employer for a decision. The Service Provider

will not be required to undertake any work involving the protection, moving or relocation of

such obstructions or services.

It is, however, the responsibility of the Service Provider to locate any obstructions or

services and the Service Provider will be responsible for any damage caused to such

obstructions or services. All such damages shall be immediately repaired and reinstated at

the expense of the Service Provider and to the satisfaction of the Employer.

Obstructions and services include cables, pipes and conduits for electricity, telephone and

telegraph connections, water, sewage, etc. as well as any other man-made or natural

structures or obstacles.



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11.13 Additional considerations

The following is a list of additional considerations that should be taken into account when

selecting a location for a monitoring site. These considerations, however, are not

mandatory and non-compliance of these factors will not invalidate a site.

a) Availability of communication links (such as telephone or cell phone).

b) Quality of road drainage.

c) Danger of lightning strikes.

d) Infestation by vermin.

e) Risk of theft and vandalism.

f) Suitability of the location for performing installation and periodic assessments and

maintenance of the system.

11.14 Site information records

The Service Provider is required to collect site information and maintain a record containing

this information for each monitoring site. The Site Provider must make a copy of the latest

record available to the Employer in electronic as well as hard copy format. Such a copy

must be provided whenever any information is added to or changed on the site particulars.

The following information must be obtained for each site and provided in the record:

a) A scaled sketch of the layout of the site, showing the location of all equipment,

sensors and auxiliary facilities. This sketch must be produced on A4 size paper.

b) Photographs of all equipment, sensors and auxiliary facilities, as well as

photographs of the roadway over a distance of at least 100 m up- and downstream

of the site.

c) Assessment of the road geometry and pavement requirements, together with any

information or data used for the assessment.

d) Site Information as specified by the South African Standard Traffic Data Collection

Format.

The Service Provider will be responsible for obtaining a site identifier for the monitoring site

as specified in the South African Standard Traffic Data Collection Format. Once a site

Identifier has been allocated to a specific site, no definition data such as traffic stream, lane

definition data, and reference site definitions may be changed.

Should there be a need to change any of the site definition data (such as when provision

must be made for additional lanes) a new site identifier must be assigned to the site. The

site information for the old site must be retained, but the old site must be marked as

“discontinued”. The old site identifier may never again be used at the particular or any other

location. The information for the new site must, however, include a reference to the old

(historical) site as well as lane number assignments.

Where use is made of partial sites, separate records must be kept for each partial site and

for the combined site. A site identifier must be allocated to each partial site and a separate

identifier to the combination site. Requirements for combination sites are specified in the

South African Standard Traffic Data Collection Format.



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12 INSTALLED AUTOMATIC MONITORING SYSTEM

REQUIREMENTS

12.1 Introduction

Only monitoring systems that carry a valid Traffic and WIM Monitoring System Certificate

issued by the Certification Organisation may be used for the provision of monitoring

services.

Installed monitoring systems must comply with the requirements specified in this chapter

in addition to relevant requirements specified in the following chapters:





This chapter also provides the requirements for the removal of a monitoring system

installation when the monitoring service is no longer necessary.

In addition to the requirements of these specifications, installed systems must also comply

with the requirements of the monitoring system manuals of the System Supplier as

specified in Chapter 3 (Traffic and WIM Monitoring System Supplier quality assurance).

It is also the responsibility of the Service Provider to institute a quality control system

according to the quality assurance requirements of these specifications as specified in

Chapter 3 (Traffic and WIM Monitoring System Supplier quality assurance requirements)

and in Chapter 4 (Traffic and WIM Monitoring Service Provider quality assurance).

12.2 Installation requirements

In addition to other requirements specified elsewhere in these specifications, installations

must also comply with the following requirements:

a) There may not be any leaking or spillage of hazardous, toxic or undesirable

materials, fluids or gases into the environment.

b) The installed system and sensors may not be aesthetically or visually obtrusive. All

parts of the system must, as far as practically possible, be hidden from view or

blended with the background.

c) There may not be any visible loose wiring or other parts protruding from the road

pavement, ground surface or equipment housing.

d) Where sensors are installed in or on the pavement, care must be taken to minimise

damage to the pavement surface. No unnecessary cutting or removal of the

pavement may be made.



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e) Where kerbs are installed along the road, cutting of such kerbs must be avoided

and conduits must be laid underneath the kerbs, where possible.

f) The monitoring system or ancillary facilities, including equipment housing,

enclosures, cages, poles, etc., may not create a hazard or danger to the traffic.

Where possible, hazardous objects must be installed behind a safety barrier, if

such a barrier is available. If not available, the clear distance between the object

and the side of the travelled roadway (not side of shoulders) may not be less than

the minimum distances provided in Table 12 for different speed limits.

g) No signs, notices or advertisements may be erected on or along the site without

the written approval of the Employer as well as the Road Authority. Such signs,

notices or advertisements may not create a danger to traffic or distract drivers. The

Employer or Road Authority has the right to have any sign, notice or advertisement

moved to another location or removed from the monitoring site.

h) After installation, all rubble, debris, dirt, materials or anything else that resulted

from the installation must be removed and the site cleaned and finished off. Any

backfilled trenches and holes must be compacted and reinstated to the original

ground level. No trees, shrubs or plants may be damaged unnecessarily and any

removed grass or plants must be replanted and watered.

Table 12 Clear distances for monitor housings or enclosures

Speed limit Minimum clear distance from side of

travel way (excluding shoulders)

60 km/h or less 5 m

70 km/h 6 m

80 km/h 7 m

90 km/h 8 m

100 km/h or more 9 m

Based on AASHTO (2006)

12.3 Removal requirements

The Employer will specify whether or not a monitoring site must be removed on completion

of a monitoring service and when the site is no longer required. In the absence of such a

specification by the Employer, the monitoring site must be removed when it is no longer

required.

Removal of a monitoring site entails the removal of all equipment, sensors, equipment

housing, auxiliary facilities, signs and notices installed by the Service Provider at the site.

Where a concrete slab was used for the monitoring housing or enclosure, the concrete

does not have to be removed if approval is obtained from the Employer. Otherwise such

concrete must also be removed.

Non-removal of a monitoring site entails the retention of all non-movable equipment,

sensors and auxiliary facilities as well as signs and notices installed by the Service Provider

at the site. Movable equipment, sensors and auxiliary facilities as well as equipment

housing are excluded and may be removed by the Service Provider. Non-movable



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equipment, sensors and auxiliary facilities are those that have been imbedded in soil, the

road pavement or in concrete. Movable equipment, sensors, equipment housing and

auxiliary facilities are those that are either not fixed, or which are fixed by means of

fasteners such as nails, screws and bolts.

Any direct or indirect damage caused by the Service Provider or the monitoring system

must be repaired by the Service Provider. These include any damage to the road, the road

pavement, kerbs, channels or any other structures along the road, as well as the

environment. The reparation must be undertaken using materials and methods approved

by the Employer and Road Authority. Damage to the road pavement may include, but is

not limited to, surface ravelling (spalling), “pumping”, potholing and subsidence of the road

or pavement.



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13 INSTALLED AUTOMATIC MONITORING SYSTEM

ASSESSMENTS

13.1 Introduction

Assessments of automatic monitoring sites and system installations must be undertaken

after the installation or removal of a monitoring system, as well as periodically during the

project to determine whether the site, together with the installed monitoring system,

complies with the requirements of these specifications. The assessments must also be

undertaken in situations where existing sites are being re-used.

This chapter describes the assessments that must be undertaken by the Service Provider

at all installed systems, as well as assessments that will be undertaken by the Certification

Organisation during the review of a Traffic and WIM Monitoring Service Provider Certificate

as specified in Chapter 2 (Service provider and monitoring system certification).

13.2 Installed monitoring system assessments

The Service Provider is responsible for undertaking the assessments specified in this

chapter, but must inform the Employer when such assessments will be undertaken. The

Employer may elect to attend and monitor the assessments. The assessments must be

undertaken as follows:

a) After installation of a system, but before monitoring is undertaken.

b) For systems other than those required for toll traffic monitoring, annually at

12 month intervals (with a grace period of two months). For systems used for toll

traffic monitoring at three-month intervals (with a grace period of three weeks).

c) When suspect data are identified during data monitoring.

d) After removal of the system.

The Certification Organisation will also undertake assessments of the monitoring site and

the monitoring system installation during a Service Provider review as specified in Chapter

2 (Service provider and monitoring system certification). Such assessments may be

undertaken at specific monitoring system installations or at randomly selected installations.

The assessments will be undertaken with the assistance of the Service Provider.

13.3 Visual assessment of the installed monitoring system

A visual inspection must be undertaken of the installed monitoring system to evaluate the

following:

a) Whether the system complies with the requirements of the monitoring system

manuals of the System Supplier, as specified in Chapter 3 (Traffic and WIM

Monitoring System Supplier quality assurance).



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b) Whether the system complies with the following requirements specified in Chapter

6 (General automatic monitoring system requirements) and Chapter 12 (Installed

automatic monitoring system requirements):

i) Whether the system has not caused undesirable environmental effects.

ii) Whether the installed system is aesthetically or visually obtrusive.

iii) Whether the sensors are fixed to the road pavement.

iv) Whether the system and sensors will not cause a road or traffic hazard or

endanger the safety of people, animals, vehicles or property.

v) Damage to the pavement surface and kerbs (where installed).

vi) Erection of signs, notices or advertisements.

vii) Removal of rubble, debris, dirt and materials and the backfilling of trenches

and holes. Replanting of grass and plants.

13.4 Monitoring system accuracy assessments

In terms of these specifications, no assessments are required of the accuracy requirements

specified in Chapter 7 (Automatic traffic monitoring system requirements) and Chapter 8

(HS WIM monitoring system requirements). The Service Provider, however, is free to

undertake such assessments and to include the results of such assessments in the

assessment report.

13.5 Installed measuring system assessment report

On completion of the monitoring site assessment, the Service Provider must prepare and

submit to the Employer an assessment report in which it is certified that the monitoring site

complies with all the relevant requirements of these specifications. No monitoring may

commence without such certification by the Service Provider.

13.6 Remedial measures

When it is found that an installed monitoring system does not comply with the requirements

of these specifications, the Service Provider will be required to apply remedial measures to

make good any defects. These measures may include the complete replacement of a

monitoring site.

The remedial measures shall ensure that the installed monitoring system complies in all

respects with the requirements of these specifications.



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14 SITE WORKS REQUIREMENTS

14.1 Introduction

This chapter provides the requirements for any work that is undertaken at an automatic

monitoring site. Such work includes the installation, maintenance and removal of the traffic

or WIM system, assessments, data extraction and any visits to the site.

The Service Provider is responsible for implementing all the requirements of this chapter.

14.2 Wayleave application

The Service Provider is responsible for applying for all wayleave applications that may be

required by the Road Authority responsible for the road, even in situations where the Road

Authority is also the Employer.

Wayleave applications are required for all new monitoring sites or at existing sites where

changes to sensors and other facilities are required. Wayleave applications must also be

made when the flow of traffic will be interfered with.

The Service Provider must obtain the wayleave from the applicable Road Authority and

submit a copy thereof to the Employer before the work is undertaken. The Service Provider

will not undertake any work without an approved wayleave.

The wayleave will allow the Service Provider to undertake the specified work, subject to

conditions in the wayleave. It is the responsibility of the Service Provider to ensure that the

conditions of the wayleave are complied with.

Under no circumstances will approval be given for the use of explosives during the work.

14.3 Work on properties outside road reserve

Where work must be undertaken on properties outside the road reserve or where there is

a need to obtain access to electricity and communication, the Service Provider must enter

into a written agreement with the owners of such properties, and submit copies of the

signed agreement to the Employer before any work is undertaken on such a property.

Such an agreement must include provisions for the following:

a) The use of and compensation for electricity and communications.

b) The reinstatement of property occupied, used, damaged or destroyed, or

compensation therefore, in lieu of reinstatement.

On completion of the project, the Service Provider must obtain a written statement from the

owner concerned, to the effect that the Service Provider has fulfilled all obligations under

the written agreement.



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14.4 Traffic accommodation

The Service Provider is responsible for the traffic accommodation measures that are

required to ensure the safe and effective passage of traffic through the site during system

installation, maintenance and removal, as well as during periodic monitoring site

assessments. No part of the work may be commenced with before adequate provision has

been made for the accommodation of traffic.

The Service Provider must comply with the traffic accommodation requirements of the latest

editions of the following documents:

a) SADC and South African Road Traffic Signs Manual.

b) The Standard Specifications for Road and Bridge Works for State Road Authorities

of the Land Transport Officials, (COLTO).

All traffic accommodation measures and road traffic signs must be removed immediately

when the measures or signs are no longer required.

14.5 Legal requirements

The Service Provider must be fully conversant with the latest enactments, provisions and

regulations of all relevant legislative and statutory bodies and shall in all respects and at all

times comply with all such enactments, provisions and regulations.

This includes any work that is undertaken adjacent to or at any infrastructure of a legislative

or statutory body, such as but not limited to, roads, railway lines, electricity lines, telephone

lines, water or oil pipelines, water channels or any other similar types of infrastructure.

The legal requirements include, but are not limited to the following:

a) The Occupational Health and Safety Act, 1993 (Act No 85 of 1993).

b) All municipal regulations, laws, by-laws and special requirements of the local

Municipality.

Part 4: Manual Traffic Count Requirements


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Part 4

Manual Traffic Monitoring

Requirements



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Part 4: Manual Traffic Monitoring Requirements

Part 4 contains the requirements for the provision of manual traffic monitoring services. The

requirements are provided in the following chapters:

Chapter 15 Manual traffic monitoring types

Chapter 16 Manual traffic monitoring site requirements

Chapter 17 Traffic monitoring fieldworker requirements



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15 MANUAL TRAFFIC MONITORING TYPES

15.1 Manual traffic monitoring

Manual traffic monitoring is monitoring that is primarily undertaken by humans, although

use may be made of mechanical and electronic equipment or devices for the monitoring.

The scope of these specifications include manual monitoring of vehicular (motorised) as

well as non-motorised traffic (e.g. pedestrians and cyclists). The Employer will specify

which traffic must be counted as well as the classification system that must be used for the

classification of vehicular as well as non-motorised traffic.

15.2 Manual monitoring types

Differentiation is made in these specifications between the following manual traffic

monitoring types:

a) Type M1 video-based monitoring in which videos are used to record traffic and the

traffic is manually monitored from the videos. This method offers the highest level

of accuracy and quality control that can be implemented with manual traffic

monitoring.

b) Type M2 individual monitoring in which devices are used to register particulars of

each passing vehicle on the road. This method offers an intermediate level of

accuracy and quality control for manual traffic monitoring.

c) Type M3 interval monitoring in which cumulative counts of passing traffic are made

in time intervals. This method offers the lowest level of accuracy and quality control

for manual traffic monitoring.

The Employer will specify the monitoring type when a manual traffic monitoring service is

required. In the absence of a type being specified by the Employer, the Type M1 manual

monitoring type must be implemented.

When a manual monitoring type is specified by the Employer (or when required in the

previous paragraph), the Service Provider will be allowed to use one of the alternative

monitoring types listed in Table 13 subject to the condition that no additional payment will

be made for the monitoring service and that payment for the service will be made at the

tariff tendered for the specified monitoring type.

Table 13 Alternative manual monitoring types

Required Monitoring types that may be used by Service Provider

type M1 M2 M3

M1

M2

M3



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May be used by Service Provider subject to conditions

15.3 Type M1 video-based monitoring

Type M1 video-based manual monitoring is monitoring in which videos are used to record

traffic and the traffic is afterwards counted manually from the videos.

The videos must be recorded using suitable video recording devices. The recorded videos

must comply with the following requirements:

a) The video must be encoded in the MPeg 4 format using the H.264 codec (ISO/IEC

14496 – Coding of audio-visual objects).

b) The video resolution must be at least 640 pixels wide and 480 pixels high.

c) The frame speed must be at least 15 frames per second.

d) The video recording may be made either in colour or in black and white (grayscale).

e) The quality of the video must be such that vehicles or non-motorised traffic can be

identified and classified on the video. When monitoring is required under dark

conditions, the quality of the video must also be such that traffic can be identified

and classified for illuminance levels of 0.001 Lux and higher.

f) Date- and timestamps must be embedded in the video metadata to allow

determination of the date and time at which each individual frame was recorded

with a resolution of at least 0.1 second. The date- and timestamps must be

recorded with an accuracy of 60 seconds from South African Standard Time.

Where multiple recorders are used at a monitoring site, the time differences

between recorders may not exceed 10 seconds.

g) The start-up and end times of the recording must be confirmed by means of a

cellular telephone, GPS (Global Positioning System) unit or a Portable Personal

Computer (laptop). Where a cellular telephone is used, it must be synchronised

with the dates and times provided by the cellular network operator. Where a laptop

is used, the laptop must be synchronised with a date and time service over the

internet in the 24 hour period prior to the monitoring service.

The number of videos recorders that must be used at a site is not prescribed in these

specifications. It is the responsibility of the Service Provider to ensure that a sufficient

number of video recorders is used to ensure the identification and classification of all

vehicles, pedestrian and cyclists passing through a site. No traffic may be obscured or

occluded by objects such as vegetation, buildings, road signs or other vehicles.

A computerised system must be used for the capturing of the traffic data from the videos.

This system must provide for the manual capturing of the data. A system may also be used

for the automatic capturing of data but all such data must be verified manually. The system

must extract date- and timestamps from the metadata embedded in the video.

Requirements for the data that must be captured and submitted to the Employer are

provided elsewhere in these specifications. In addition to this data, copies of all video

recordings made during a monitoring service must also be submitted to the Employer. The

Employer may use these video recordings in a quality control system to verify that the traffic

data have been captured correctly by the Service Provider. The Service Provider will not

be involved in this verification and will not be responsible for such verification.



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15.4 Type M2 individual monitoring

Type M2 individual monitoring is monitoring in which electronic recorders are used to

manually record the dates and times as well as other particulars of individual vehicles or

non-motorised traffic passing through a site.

The recorders used for the monitoring must comply with the following requirements:

a) The recorders must be capable of capturing the date- and timestamps of all button

presses. The timestamps must be recorded with a resolution of at least 0.1 second

and with an accuracy of 60 seconds from South African Standard Time. Where

multiple recorders are used at a monitoring site, the time differences between

recorders may not exceed 10 seconds.

b) Sufficient buttons must be available on the recorder to differentiate between the

different travel directions, turning movements, lanes (when required) and vehicle

types. A button must be available which can be used to cancel a previously

recorded button.

c) The recorders must give either a tactile or audible feedback to the operator when

a button is pressed.

d) The start-up and end times of the recording must be confirmed by means of a

cellular telephone, GPS (Global Positioning System) unit or a Portable Personal

Computer (laptop). Where a cellular telephone is used, it must be synchronised

with the dates and times provided by the cellular network operator. Where a laptop

is used, the laptop must be synchronised with a date and time service over the

internet in the 24 hour period prior to the monitoring service.

The number of recorders that must be used at a site is not prescribed in these

specifications. It is the responsibility of the Service Provider to ensure that a sufficient

number of operators with recorders is used to ensure that all vehicles or non-motorised

traffic passing through a site are recorded.

A computerised system must be used for the extraction of the traffic data from the

recorders. This system must be capable of extracting the date- and timestamps and to

convert the button presses to the required traffic data.

Requirements for the required data that must be extracted and submitted to the Employer

are provided elsewhere in this chapter and specifications.

15.5 Type M3 interval monitoring

Type M3 interval monitoring is monitoring in which individual events are not recorded and

only cumulative counts are obtained during time intervals. Counts can be made of vehicles

or non-motorised traffic passing through a site.

The following equipment must be used for the cumulative counts:

a) Manually operated counters are used to record vehicles or non-motorised traffic.

Either mechanical or electronic equipment may be used. The equipment must be

able to continually display the cumulative count. The counters must provide audible

or tactile feedback to the operator when a button is pressed.



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b) At least one cellular telephone or Portable Personal Computer (laptop) must be

used by the survey team at the site. Where a cellular telephone is used, it must be

synchronised with the dates and times provided by the cellular network operator.

Where a laptop is used, the laptop must be synchronised with a date and time

service over the internet in the 24 hour period prior to the monitoring service. The

telephone or laptop must be capable of emitting an audible sound at the time when

the count must commence and then at the end of each time interval during the

traffic count.

c) Each fieldworker must be issued with one or more data forms on which the

cumulative traffic counts are captured. The capturing must be done by means of

pens using indelible (permanent) ink. At least two pens must be issued to each

fieldworker.

d) Unless otherwise specified by the Employer, the traffic counts must be captured in

15-minute intervals.

A GPS enable camera capable of taking geo-tagged photos of the completed data forms

at the monitoring site. The camera must also be capable of authenticating the photos.

Alternatively, a portable personal computer (laptop) may be used for such

authentication.The number of fieldworkers that must be used at a site is not prescribed in

these specifications. It is the responsibility of the Service Provider to ensure that a sufficient

number of fieldworkers is used to ensure that all vehicles or non-motorised traffic passing

through a site are recorded.

The data forms that must be used by the fieldworker will be prescribed or issued by the

Employer. In the absence of such prescribed or issued forms, the Service Provider may

use its own forms provided that all relevant data are captured. The data forms must, as a

minimum, provide for the capturing of the following information and data:

a) Location at which the monitoring service is provided (including GPS coordinates).

b) Date of the monitoring service (including the day of the week).

c) Weather condition during the monitoring service.

d) Times for each time interval over which traffic is monitored.

e) Travel directions, turning movements and lanes for which counts are recorded.

f) Different vehicle types for which counts are recorded.

g) Cumulative traffic counts.

h) Signatures of the fieldworkers undertaking the count.

i) Signature of the supervisor.

A computerised system must be used for the capturing of the traffic data from the data

forms. This system must provide for the manual capturing of the data. A system may also

be used for the automatic capturing of data but all such data must be verified manually.

Photos of the data forms must be taken at the monitoring site on completion of the

monitoring service. The purpose of these photos is to verify that the forms have not been

amended or changed after completion of a traffic monitoring service. A GPS enabled

camera capable of taking geo-tagged photos must be used. Each photo must be date- and

timestamped and the GPS location must be included in the metadata of the photo. The

photos together with the metadata must also be authenticated in accordance to the

requirements of Chapter 19 (Monitoring data requirements). The quality of the photos must

allow the required verification of the data forms. Photos must be taken and submitted in the

JPG Joint Photographic Experts Group Format.



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Requirements for the required data that must be captured and submitted to the Employer

are provided elsewhere in this chapter and specifications. In addition to this data, the

Service Provider must also submit the original data forms (as completed during the

monitoring service) together with the authenticated photographic images of the data forms

to the Employer.

The Employer may use the submitted forms and photographic images in a quality control

system to verify that the traffic data have been captured correctly by the Service Provider.

The Service Provider will not be involved in this verification and will not be responsible for

such verification.

15.6 Employer quality control measures

The Employer may implement a quality control system that is aimed at verifying that traffic

data have been captured and submitted correctly by the Service Provider. The Employer

will be responsible for the implementation of such a quality control system or may employ

the services of another service provider for this purpose. The Service Provider providing

the monitoring service will not be involved or responsible for this quality control. The Service

Provider, however, is responsible for implementing quality assurance measures that are

aimed at ensuring that data are captured correctly and may not rely on the quality control

measures of the Employer for this purpose.

Accuracy requirements are provided in this section for the verification of the captured data.

Should any non-compliance with these accuracy requirements be found, the Employer may

request the Certification Organisation to review the quality assurance measures

implemented by the Service Provider. Such review will be considered to form part of the

normal review process by the Certification Organisation and the Service Provider will be

responsible for all costs and submissions required for such review.

The Employer may undertake the following verification as part of the quality control system

(note that no verification is required for Type M2 individual monitoring):

a) For Type M1 video-based monitoring, verification of whether vehicles and vehicle

categories have been captured correctly from video recordings.

b) For Type M3 interval monitoring, verification of whether traffic data have been

captured correctly from the data forms. A separate verification will also be

undertaken to compare the data forms with the photographic images to determine

whether the forms have been amended or changed after completion of the

monitoring service.

A sample of vehicles or data entries will be randomly selected from the videos or the data

forms for the verification of whether data have been captured correctly. The sample can be

selected from either one video or data form or from a multiple of videos or data forms.

Recommended sampling rates are given below but the Employer may select any other rate

that is considered appropriate:

a) Type M1 video-based monitoring: 1% of vehicles or non-motorised traffic.

b) Type M3 interval monitoring: 10% of data entries.



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The accuracy requirements for the captured data are specified in terms of the maximum

allowable limit for the number of errors found in a count, expressed as a percentage of the

total count in the sample. The total count in a sample will be determined as follows.

a) Type M1 video-based monitoring: The total number of vehicles or non-motorised

traffic that have been included from the videos in the sample.

b) Type M3 interval monitoring: The total number of vehicles or non-motorised traffic

obtained from the different entries selected from the data forms for inclusion in the

sample.

Erroneous counts will be determined as follows:

a) Type M1 video-based monitoring: The number of vehicles or non-motorised traffic

that were missed (not counted), created (invented) or which has been incorrectly

classified by the Service Provider.

b) Type M3 interval monitoring: The sum of the absolute values of the differences

between the actual count in the different data entries and the counts submitted by


The proportion (percentage) of erroneous counts in the sample is determined by means of

the following formula:

P = 100 ∙E

R

In which:

P = Proportion (percentage) of erroneous counts in sample

E = Error count in sample

R = Total count in sample

The percentage of erroneous counts determined by means of the above formula may not

exceed the maximum allowable percentages provided in Table 14 for different types of

errors. The minimum sample sizes that must be used for the verification are also provided

in the table.

Table 14 Manual monitoring maximum allowable percentage errors

Monitoring type Error description Minimum sample

size (number)

Max allowable

error (%)

Type M1 video Vehicles or non-motorised traffic missed (not

captured) or created (invented)

2000 0.5%

Vehicles or non-motorised traffic not

categorised, or wrongly categorised

2000 1.0%

Type M3 interval Absolute differences between actual and

submitted counts

5000 0.5%



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15.7 Traffic data requirements

Requirements for the submission of traffic data to the Employer are provided in Chapter 19

(Monitoring data requirements) of these specifications. Requirements are provided for the

format in which data must be submitted as well as the authentication of the submitted data.

Manual traffic count data must be submitted in the format specified in the South African

Standard Traffic Data Collection Format, including all the data required to produce the

header records defined by the format. Individual counts must be provided in the individual

vehicle data format while cumulative counts must be provided in the summary data format

specified in the format.

Traffic data must be captured and recorded when traffic crosses a specific line at the site.

On road links, imaginary lines must be identified over the full width of the road. At

intersections, the traffic must be recorded when crossing the stop or yield lines at the

intersection or imaginary lines when such lines are not available. Vehicles must be captured

when the rear axles of the vehicles cross the lines.

The following data must be captured and provided for individual traffic data:

a) Departure date and time. The departure date and time on and at which the rear

axle of the vehicle crosses a specific line on the site. Dates and times must be

recorded in South African Standard Time, which is the Universal time (Greenwich

Mean Time) plus 2 hours. The recording may not change should Daylight Saving

Time be introduced in the country.

b) Lane number (physical or virtual). Lane numbers must be defined in accordance to

the requirements of the South African Standard Traffic Data Collection Format. For

traffic monitoring in which per-lane capturing is not required, the different travel

directions or movements must be handled as traffic lanes.

When required by the Employer, reversing vehicles will be captured in virtual lanes.

In situations where overtaking occurs, overtaking vehicles must not be handled as

reversing vehicles and must be captured in the appropriate direction of travel (using

virtual lanes if required by the Employer).

c) Vehicle class. The classification of the vehicle as specified below.

Cumulative counts must be converted to non-cumulative counts per time interval before it

can be provided in accordance to the format. The following data are required:

a) Date and time. The date and time must be provided for the end of each time

interval.

b) Interval duration. The duration of the each time interval.

c) Lane number (physical or virtual). Lane numbers must be defined in accordance to

the requirements of the South African Standard Traffic Data Collection Format.

Lane numbers can also be used to define the different turning movements at an

intersection.

d) Classified counts. The non-cumulative count per vehicle class as specified below.

Vehicles must be classified in accordance to the vehicle categories as specified in the

South African Standard Traffic Data Collection Format. The Employer will specify the

required vehicles categories for each count (including any non-motorised traffic). In the

absence of such specification, no classification will be undertaken.



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16 MANUAL TRAFFIC MONITORING SITE

REQUIREMENTS

16.1 Link and intersection monitoring

Requirements are provided in this chapter for the monitoring sites at which manual traffic

monitoring services may be provided. Differentiation is made between the following site

types:

a) Link monitoring sites.

b) Intersection monitoring sites.

When specifying a manual traffic monitoring service, the Employer must specify whether

link or intersection monitoring is required.

16.2 Link monitoring sites

Link traffic monitoring is undertaken on road sections between intersections. A link

monitoring site is a single location where all lanes of traffic are monitored as specified by

the Employer.

The link monitoring site may be either some distance from an intersection or directly

adjacent to the intersection. The Employer must either specify the location of the site or the

road link on which the monitoring must be undertaken. When a road link is specified, the

Service Provider is responsible for identifying the location of the monitoring site on the link.

In such cases, locations must be selected which are reasonably representative of average

traffic volumes on the road link.

The following requirements apply to link monitoring sites:

a) The link monitoring must be undertaken for both directions of travel and the

monitoring must differentiate between the two directions.

b) On double carriageway roads, the monitoring must be undertaken on both

carriageways, even if the carriageways are some distance apart.

c) Traffic counts must be made of traffic (vehicles or non-motorised traffic) travelling

over an imaginary straight line over the width of the roads. For vehicle counts, the

counts must be made when the rear axles of the vehicles cross this line.

d) The Employer may specify that the monitoring be undertaken per lane. Such

monitoring must differentiate between the different lanes in the two directions of

travel (unless otherwise specified by the Employer).



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16.3 Intersection monitoring sites

Intersection traffic monitoring is undertaken at intersections. An intersection monitoring site

is a single intersection where all lanes of traffic travelling through the intersection are

monitored as specified by the Employer.

These specifications only provide for manual traffic monitoring at priority or signal controlled

intersections. Roundabouts and interchanges are excluded from the scope of these

specifications. Manual monitoring of individual intersections forming part of roundabouts or

interchanges are, however, included in the scope of the specifications.

The following requirements apply to intersection monitoring sites:

a) The intersection monitoring must be undertaken for all approaches to the

intersection and must differentiate between the different turning movements from

each approach.

b) For intersection consisting of three or four approaches, differentiation must be

made between left-turn, straight-through and right-turn movements. For

intersections with five or more approaches, the turning movements must be

identified in terms of the exit legs from the intersections.

c) Traffic counts are made at the stop or yield line positions on the approaches to the

intersection. Where no such lines are provided, an imaginary line over the width of

the road must be selected. For vehicle counts, the counts are made when the rear

axles of vehicles cross this line.

d) The Employer may specify that the monitoring be undertaken per lane. When

specified, the count must differentiate between the turning movements possible

from each lane on each approach to the intersection. When lane monitoring is not

specified, differentiation is only required between the possible turning movements

from each approach.

16.4 Monitoring site stratification

Manual traffic counts must be expanded to equivalent annual traffic characteristics using

expansion factors derived by means of a stratification system. The stratification systems

(one or more) that must be used for this purpose is defined in TMH 8 (COTO, 2015).

The stratification system requires that monitoring sites must be grouped into stratification

strata and clusters consisting of one or more monitoring sites with similar characteristics.

Each stratum must contain at least one long-term monitoring site. For each stratum or

cluster, a set of expansion factors and typical traffic characteristics must be derived from

the long-term sites that can be used for deriving equivalent annual characteristics at the

short-term sites.

The Service Provider in co-operation with the Employer will be responsible for implementing

the stratification system, including the grouping of monitoring sites in strata and clusters

(unless otherwise specified by the Employer). The Employer will specify the software that

must be used by the Service Provider for this purpose. In the absence of such

specifications, the software specified by the South African National Road Agency Ltd

(SANRAL) shall be used for this purpose.



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16.5 Site information records

The Service Provider is required to collect site information and maintain a record containing

this information for each monitoring site. The Site Provider must make a copy of the latest

record available to the Employer in electronic as well as hard copy format. Such a copy

must be provided whenever any information is added to or changed on the site particulars.

The following information must be obtained for each site and provided in the record:

a) The site information specified by the South African Standard Traffic Data Collection

Format.

b) Scaled sketch of the site. This sketch must be produced on an A4 size and must

show the following information:

i) Site ID Number.

ii) Route, road and section numbers and kilometre markers.

iii) Travel directions, turning movements and destinations.

iv) Carriageway, lane or turning movement numbers.

v) North direction arrow.

The sketch showing the above information must be prepared before

commencement of the traffic monitoring. On the day of the monitoring service, the

following information must be manually added to the sketch by the monitoring team:

i) Date of the monitoring service.

ii) The position of each fieldworker or recording equipment on the site. The

fieldworkers or recording equipment must be marked by means of a letter

code (e.g. A, B, C etc).

iii) The lanes of traffic (directions or turning movements) that were monitored

by a specific fieldworker. The letter codes must be used to indicate the

monitored lanes.

c) Photos (one or more) of the site showing sufficient detail to allow identification of

the site from the photos. The purpose of these photos is to verify that the manual

traffic service has been provided at the correct location. The photos must be taken

by the monitoring team at the site on the date the monitoring service is provided.

The photos must be taken with a GPS enabled camera capable of taking geo-

tagged photos. Each photo must be date- and timestamped and the GPS location

must be included in the metadata of the photo. These images must also be

authenticated in accordance to the requirements of Chapter 19 (Monitoring data

requirements). Photos must be taken and submitted in the JPG Joint Photographic

Experts Group Format.

The Service Provider will be responsible for obtaining a site identifier for the monitoring site

as specified in the South African Standard Traffic Data Collection Format. Once a site

Identifier has been allocated to a specific site, no definition data such as traffic stream, lane

definition data, and reference site definitions may be changed.

Should there be a need to change any of the site definition data (such as when provision

must be made for additional lanes) a new site identifier must be assigned to the site. The

site information for the old site must be retained, but the old site must be marked as

“discontinued”. The old site identifier may never again be used at the particular or any other



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location. The information for the new site must, however, include a reference to the old

(historical) site as well as lane number assignments.



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17 TRAFFIC MONITOR FIELDWORKER REQUIREMENTS

17.1 Traffic monitor fieldworker requirements

Requirements are provided in this chapter that are applicable to fieldworkers involved with

the provision of manual traffic monitoring services.

In addition to the requirements provided in this chapter, the Service Provider must in all

instances be fully conversant with the latest relevant enactments, provisions and

regulations of all relevant legislative and statutory bodies and shall in all respects and at all

times comply with all such enactments, provisions and regulations. The legal requirements

include the following:

a) All relevant national and provisional legislation that are applicable to the

employment and safety of fieldworkers.

b) All municipal regulations, laws, by-laws and special requirements of the local

Municipality.

17.2 Communication facilities

At least one cellular telephone must be made available to fieldworkers at each monitoring

site that can be used for emergency (and other) purpose. The following telephone numbers

must be made available to the fieldworkers:

a) Service Provider.

b) South African Police.

c) Ambulance services.

17.3 Relief fieldworker

The requirements of this section are applicable to Types M2 and M3 manual monitoring.

For these types of monitoring, the Service Provider must, at all monitoring sites, make at

least one relief fieldworker available that can take over the duties of other fieldworkers in

situations where a fieldworker needs a break or where the fieldworker cannot continue with

the traffic monitoring due to an emergency situation.

The Service Provider must issue instructions to fieldworkers that no fieldworker is allowed

to stop the traffic monitoring unless the duties of the fieldworker is taken over by the relief

fieldworker. A sufficient number of fieldworkers must be available at all times to undertake

a complete monitoring service.



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17.4 Ablution facilities

The Service Provider is responsible for making ablution facilities available to fieldworkers.

These facilities must include the following:

a) A toilet (any type).

b) A facility for cleaning or washing hands (any type of facility).

The facilities may be one of the following two types:

e) A facility that is open to the public (e.g. at a filling or service station).

f) Portable facility with some form of enclosure (such as a tent).

The ablution facilities must be available at a walking distance of not further than 500 m from

the site.

17.5 Road safety

The Service Provider is required to institute measures that are aimed at ensuring that traffic

monitoring does not create a traffic hazard or which endangers the safety of the public,

fieldworkers, animals, vehicles and property.

Fieldworkers must be instructed to position themselves as far as practically possible from

the travelled roadways, including paved shoulders. The distance between the fieldworkers

and the travel way (excluding shoulders) may not be less than the minimum distances

provided below for different speed limits. Where a safety barrier is available, the

fieldworkers may position themselves behind the barrier at distances closer that that

provided in the table.

Speed limit Minimum distance from side of travel

way (excluding shoulders)

60 km/h or less 3 m

70 – 90 km/h 5 m

100 km/h or more 7 m

Part 5: Monitoring Service and Data Requirements


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Part 5

Monitoring Service and Data

Requirements



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Part 5 contains the requirements that are applicable to the provision of monitoring services

and the data that must be collected and provided as part of automatic and manual traffic

monitoring and WIM services. The requirements are provided in the following chapters:

Chapter 18 Monitoring service requirements.

Chapter 19 Monitoring data requirements.



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18 MONITORING SERVICE REQUIREMENTS

18.1 Introduction

This chapter provides the requirements applicable to the provision of automatic as well as

manual traffic monitoring services. These requirements relate to the type, start date and

duration of the monitoring services and the programming of the services.

18.2 Monitoring service types

The types of monitoring services that can be provided in terms of the specifications are the

following:

a) Automatic monitoring services

i) Traffic monitoring using one of the monitoring system types and accuracy

levels defined in Chapter 7 (Automatic traffic monitoring system

requirements).

ii) Toll monitoring according to one of the traffic monitoring types and

accuracy levels defined in Chapter 7 (Automatic traffic monitoring system

requirements).

iii) Integrated Traffic and HS WIM monitoring. The type and accuracy level of

the traffic monitoring system must be specified as defined in Chapter 7

(Automatic traffic monitoring system requirements).

iv) HS WIM monitoring without traffic monitoring. Where the system will be

used for screening purposes, the required screening facilities must be

specified.

v) LS WIM monitoring.

b) Manual traffic monitoring services

i) Manual link traffic monitoring in which traffic is counted on road links

between intersections.

ii) Manual intersection traffic monitoring in which traffic is counted passing

through intersections.

18.3 Monitoring start dates

The Employer will specify the date on which specific automatic or manual monitoring

services must be started. The start date may be specified as a specific starting date or over

a period of time. Alternatively, the Employer may also specify a period during which the

monitoring services must be undertaken and completed.



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The Service Provider will not be required to start more monitoring services per month than

the following during any month of the contract period (unless otherwise agreed to by the

Service Provider):

a) Automatic monitoring

i) Twenty equivalent monitoring services per month, when the required total

number of equivalent services is less than 200.

ii) Ten per cent of the total number of equivalent monitoring services per

month, when the required total number of equivalent services is 200 or

more.

b) Manual traffic monitoring

i) Forty manual traffic count services per month, when the required total

number of equivalent services is less than 400.

ii) Ten per cent of the total number of manual traffic count services per month,

when the required total number of services is 400 or more.

The Employer may require that the above maximum number of equivalent monitoring

services be started in consecutive months or over different months during the contract

period. The requirements, however, imply that the Service Provider may be given the

following minimum number of months at the start of the project for the commencement of

all the required monitoring services:

a) Automatic monitoring

i) The total number of equivalent monitoring services divided by 20, when

the required total number of equivalent services is less than 200.

ii) A period of 10 months, when the required total number of equivalent

services is 200 or more.

b) Manual traffic monitoring

i) The total number of manual traffic monitoring services divided by 40, when

the required total number of services is less than 400.

ii) A period of 10 months, when the required total number of services is 400

or more.

For automatic monitoring, the equivalent number of monitoring services will be determined

by means of the following formula:

Equivalent number of monitoring services =

1 x No of traffic monitoring services without HS WIM monitoring +

2 x No of monitoring services with HS WIM monitoring +

2 x No of Toll traffic monitoring services

The Service Provider must start a service during the period specified by the Employer.

Where a service is started earlier than the specified date, no payment will be made for

services provided before the required start date (unless otherwise agreed to by the

Employer). Where a service is started later than the specified date, such monitoring will be

regarded as missing data in terms of the requirements specified in Chapter 19 (Monitoring

data requirements).



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18.4 Monitoring durations

In terms of these specifications, automatic traffic and WIM monitoring services can be

provided over the following durations:

a) 1-Day monitoring. One full 24-hour Normal day must be monitored. The day must

be a Normal Monday, Tuesday, Wednesday, Thursday or Friday. Saturdays or

Sundays may not be monitored except when otherwise specified by the Engineer.

b) 2-Day Monitoring. Two Normal days must be monitored. The days may be any

Normal weekday (Monday to Fridays). Saturdays or Sundays may not be

monitored except when otherwise specified by the Engineer. The two days do not

have to be consecutive but may not further than 3 months apart. Both days must

be from the same calendar year.

c) 7-Day Monitoring. A total of 7 Normal days must be monitored. Each day of the

week (Mondays to Sundays) must be counted at least once on a Normal day. The

monitoring does not have to be undertaken on consecutive days but none of the

days may be further than 3 months apart. All days must also be from the same

calendar year.

d) 14-Day Monitoring. A total of 14 Normal days must be monitored. Each day of the

week must be counted on at least two Normal days. The count does not have to

be taken on consecutive days but none of the days may be further than 3 months

apart. All days must also be from the same calendar year.

e) 3-Month Monitoring. The monitoring must be undertaken over a period of 3

consecutive calendar months. Such monitoring must be undertaken on Normal and

Abnormal days. Unless otherwise required by the Employer, all months must be

from the same calendar year.

f) 1-Calendar Year monitoring. This monitoring must be undertaken over a period of

one calendar year starting on 1 January and terminating on 31 December in a

specific year. A grace period is allowed in which the monitoring may be started not

earlier than 1 November in the previous year or not later than 1 March in the

following year and continued for a period of 12 months. The monitoring must be

undertaken on Normal as well as Abnormal Days.

g) Long-term monitoring. The monitoring must be undertaken in periods specified in

6-month duration intervals (e.g. 6, 12, 18 … months). The monitoring will start on

dates specified by the Employer and continue for the specified durations. The

monitoring must be undertaken on Normal as well as Abnormal Days.

h) Toll traffic monitoring. The monitoring must be undertaken in periods specified in

6-month duration intervals (e.g. 6, 12, 18 … months). The monitoring will start on

dates specified by the Employer and continue for the specified durations. The

monitoring must be undertaken on Normal as well as Abnormal Days.

Manual traffic monitoring must be undertaken on days as specified by the Employer. When

not specified, the count must be undertaken on a Normal Monday, Tuesday, Wednesday,

Thursday or Friday. Monitoring may be undertaken over the following durations:

i) Specific hours. Traffic monitoring will be undertaken over one or more specific

hours of the day as specified by the Employer. These hours may be either



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continuous or discontinuous over the 24 hours of one calendar day. When

discontinuous, the traffic monitoring for the day will be regarded as a single

monitoring service.

j) 12-Hour monitoring. Monitoring must be undertaken over a continuous period of 12

hours. The start and end times will be specified by the Employer. When not

specified, the monitoring must start at 06:00 and end at 18:00.

k) 18-Hour monitoring. Monitoring must be undertaken over a continuous period of 18

hours. The start and end times will be specified by the Employer. When not

specified, the monitoring must start at 04:00 and end at 22:00.

Definitions of Normal and Abnormal Days are provided in Appendix B of these

specifications.

The Service Provider will be required to submit “complete” data sets (as defined in Chapter

19 (Monitoring data requirements) for the full monitoring durations as defined above. In

situations where the Service Provider was unable to provide such complete data sets for

the full monitoring durations, payment will only be made for the complete data sets as

specified in Chapter 21 (Payment requirements)). The Service Provider may, however,

make an offer to either repeat or extend the monitoring at its expense in order to achieve

complete data sets. The Employer may either accept or reject such an offer.

The Employer may change the required duration of a long-term or a toll traffic monitoring

service at a site at any time before or during the monitoring service. The duration may be

changed to any of the 6-month duration intervals provided for in the tender. Payment for

the service will be made in terms of the changed duration as specified in Chapter 21

(Payment requirements). In situations where a long-term or toll traffic monitoring service

has already started, the start date may not be changed. The duration may also not be

decreased to a period shorter than the duration of service that has already been provided.

The Employer may discontinue any monitoring service at any time during a monitoring

service. Payment for such discontinued services will be made in terms of the requirements

provided in Chapter 21 (Payment requirements).

18.5 Monitoring programme

The Employer will specify the monitoring (automatic or manual) sites, types, start dates, as

well as monitoring durations at the start of the project. The Service Provider is responsible

for preparing a detailed programme according to which the monitoring will be undertaken

over the project period and must submit the programme to the Employer for approval. The

programme must be submitted to the Employer before monitoring may commence.

The Employer may change the monitoring locations, types, dates and durations at any time

during the project (including after a monitoring service has already commenced) in which

case the Service Provider will be required to submit a revised programme. The Service

Provider will inform the Employer if it is not possible to revise the monitoring programme to

accommodate the changes. In such cases, the Employer and the Service Provider must

cooperate to establish the changes that can be accommodated.

The programme must provide details on the following aspects of the monitoring services:

a) Automatic monitoring (these are not required for manual traffic monitoring)



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i) Dates on which wayleave applications will be made.

ii) Dates on which monitoring sites will be constructed and installed.

b) Automatic and manual monitoring

i) Dates during which the sites will be monitored.

ii) Expected dates for road construction and rehabilitation on specific roads.

The programme must make provision for any construction or rehabilitation work that may

be planned for a particular road. It is the responsibility of the Service Provider to regularly

obtain information regarding planned roadworks from the Road Authority concerned. The

programme must have sufficient flexibility to accommodate possible changes to the

roadworks programme and must be adjusted when such changes occur. No extension of

time will be given as a result of the roadworks, and if monitoring cannot be undertaken

during the required time, the specific monitoring will be considered as not being required.

The programme must also allow some flexibility for the possible impact of adverse weather

conditions, including abnormal rainfall, on the monitoring site construction and installation.

No extension of time will be given as a result of adverse weather conditions.

Monthly reports on the progress with the programme must be submitted to the Employer.

The monthly reports must show the following information for each of the monitoring service

types:

a) Wayleaves (automatic monitoring only)

i) The total number of wayleaves that are required.

ii) The number of applications for wayleaves that should have been made.

iii) The number of wayleave applications that have actually been made.

iv) The number of approved wayleaves.

b) Monitoring sites

i) The total number of monitoring sites that will be required.

ii) The number of monitoring sites that should have been installed.

iii) The number of monitoring sites that have been installed and which have

been certified by the Service Provider.

c) Monitoring services (quantities are either number of days or hours)

i) The total quantity of services that is required.

ii) The quantity of services that should have been completed.

iii) The quantity of services that have been completed.

Should the Service Provider fall behind the approved programme, the programme must be

adjusted and resubmitted to the Employer for approval. The revised programme must be

submitted within seven days of the date on which the Service Provider received a notice to

this effect from the Employer. Proposed revisions to monitoring types, start dates and

durations must be approved by the Employer. The adjusted programme must reflect how

the monitoring will be completed within the required project time period.

18.6 Monthly meetings

When required by the Employer, the Service Provider must attend monthly meetings with

the Employer. The purpose of these meetings is to evaluate the progress that has been

made with the traffic monitoring and to discuss any matters pertaining to the traffic



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monitoring. The venues, dates and times of such meetings shall be determined by the

Employer.

18.7 Non-performance

The Employer may, at its discretion, terminate the contract in the event that the Service

Provider falls behind the monitoring programme to the extent that:

a) Less than 85% of the monitoring sites that should have been installed according to

the monitoring programme have been installed; or

b) The quantity (measured in terms of days or hours monitored) of monitoring services

that have been completed is less than 85% of the services that should have been

completed according to the monitoring programme.

The latest monitoring programme that has been approved by the Employer shall be used

to determine the above percentages.



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19 MONITORING DATA REQUIREMENTS

19.1 Introduction

This chapter provides the requirements for the automatic and manual traffic monitoring data

that must be submitted, the format of such data, as well as the verification and analysis

required for such data.

19.2 Data collection and extraction

The automatic and manual traffic monitoring data that must be collected are specified in

the different chapters of these specification. All traffic data must be collected for individual

vehicles and not in summary formats (except for manual interval traffic monitoring).

The Service Provider is responsible for the extraction and collection of the data collected

at monitoring sites. Such data collection can be undertaken by any method deemed suitable

by the Service Provider.

Where a Traffic and HS WIM system is used for the screening of vehicles at a static

weighbridge, the data must be extracted and submitted to the weighbridge control system

by means of a data communication system.

19.3 Data conversion

The data collected during the automatic or manual traffic monitoring service must be

converted to the format specified in the South African Standard Traffic Data Collection

Format by the Service Provider. The data that are required include the following, as

specified in this Data Collection Format:

a) Header records.

b) Individual vehicle data.

c) Site definition data.

19.4 Data authentication

This section provides requirements for the authentication of data that are submitted to the

Employer. Any data that are not authentication in accordance with these requirements will

be regarded as missing data by the Employer (unless otherwise agreed to by the

Employer).

The Employer will specify the data authentication software that must be used by the Service

Provider for the authentication of collected data. In the absence of such specifications, the

software specified by the South African National Road Agency Ltd (SANRAL) shall be used

for this purpose. Authentication software will be provided for the following two purpose:



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a) Authentication of traffic data

b) Authentication of photographic images

Traffic data authentication must be undertaken after conversion of the data to the format

specified in the South African Standard Traffic Data Collection Format. The authentication

must be completed within a period of one hour after data were extracted from the monitoring

system. The following data authentication is required:

a) Automatic traffic monitoring. Data authentication is required for all automatic traffic

monitoring types and systems.

b) Manual traffic monitoring, Data authentication is only required for manual Type M2

individual monitoring and not for other manual monitoring types.

Photographic image authentication is only required for manual traffic monitoring and not for

automatic traffic monitoring. The authentication must be completed within a period of two

hours after completion of the monitoring service. Authentication is required of the following

photographic images:

a) Site photographs required for the verification of the location of the monitoring

service. This authentication is required for all manual monitoring types.

b) Photographic images of traffic data forms completed as part of Type M3 interval

monitoring.

The period of one hour specified for traffic data authentication is measured from the time

of commencement of the extraction until the authentication by means of the software is

completed. Within this one hour period, the data must be extracted, converted to the format

specified in the South African Standard Traffic Data Collection Format and authenticated

by means of the provided authentication software.

The period of two hours specified for photographic image authentication is measured from

the time of completion of the monitoring services until authentication by means of the

software is completed. Within this two hour period, the photographs must be taken, date

and timestamped, GPS coordinates added to the photo metadata and the photos

authenticated by means of the provided authentications software.

In situations where it is not possible to authenticate the data within the above periods, the

Service Provider may submit reasons to the Employer for the late authentication. The

Employer, will at its discretion, accept or reject such late authentication.

The authentication software will require a connection to either the Internet or to a GPS

(Global Positioning System) unit. The GPS unit must be used in situations where Internet

services are not available. Such a connection is required to verify the date and time at

which the authentication was undertaken.

The authentication software will append an encrypted code to the converted data file that

will authenticate the contents of the data file, as well as the name of the file. Neither the

contents nor the name of the file may be changed after the data file has been authenticated.

Such a change will invalidate the authentication of the data file.

The names of the submitted data files must comply with the requirements of the South

African Standard Traffic Data Collection Format.



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19.5 Data submission

The Employer will specify the time period in which authenticated data (automatic or manual)

must be submitted to the Employer. In the absence of such a specification, the

authenticated data must be submitted within a period of 24 hours after extraction.

Unless specified otherwise by the Employer, the data must be submitted over the internet

via a Hypertext Transfer Protocol Secure (HTTPS) based Representational State Transfer

(REST) type Web Service with authentication headers. The data exchange format must be

based on the JavaScript Object Notation (JSON) as specified by the Employer. Where the

Employer does not have such a service available, the Service Provider must provide the

Employer with a service to be used for the downloading the data over the internet.

19.6 Data verification

The Employer will specify the data management software that must be used for the

verification and analysis of collected data (automatic or manual). In the absence of such a

specification, the software system specified by the South African National Road Agency

Ltd (SANRAL) shall be used for this purpose.

The purpose of data verification is to determine whether the submitted data are correct and

error free. The data management software will verify the data on three levels, and the

Service Provider will be required to undertake all three levels of tests. Payment will be made

for monitoring services if the data passes the first two levels of tests.

The test levels are as follows:

a) First level tests are undertaken on submission of data to the software. The tests

include the authentication of the submitted data.

b) Second level tests are undertaken on a monthly basis (calendar months) or when

the monitoring duration is shorter than one month.

c) Third level tests are usually undertaken on an annual basis (calendar years) but

may be undertaken over a shorter period when data are not available for a whole

year. These tests will not affect payment for monitoring services.

An overview of the above tests is provided in Appendix D to these specifications.

Some of the tests include tests that are undertaken to verify that the data comply with the

requirements of the South African Standard Traffic Data Collection Format. Tests will also

be undertaken to authenticate the data. Should any data fail these tests, then the whole file

will be rejected and will not be processed further.

Some of the tests also include tests that are undertaken to identify “suspect” and “bad”

data. When such data are identified, a report will be created listing the data and this will be

made available to the Service Provider. It will be the responsibility of the Service Provider

to investigate the data and to identify possible causes or reasons why the data are suspect,

and to make recommendations on whether the data should be accepted or rejected. The

Employer will decide whether the Service Provider will be allowed to mark accepted data

as “good” and rejected data as “bad”.

The Service Provider may also submit recommendations for amending submitted data. The

Employer will decide whether the Service Provider will be allowed to amend the data (and



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if necessary resubmit the data). Where the Service Provider is allowed to amend and/or

resubmit the data, the full set of verification tests must be repeated for amendment data.

In situations where the Employer requires a monitoring service at a monitoring site that

does not comply with the road geometry and pavement requirements specified in Chapter

11 (Automatic monitoring site requirements), the Service Provider will indicate whether data

marked as “bad” have been affected by such non-compliance. Such data will then be

marked as “uncertain” rather than “bad”. For payment purposes, such data will be

considered to be “good” data.

Some of the tests also include tests that are undertaken to identify periods with “missing”

data. These are periods in which no data have been collected, or periods in which complete

data sets are not available.

19.7 Data verification periods

The data verification specified in the previous section must be completed by the Service

Provider within the following time periods:

a) For monitoring durations shorter than one month, the data verification must be

completed within three weeks after the monitoring has been undertaken.

b) For monitoring longer than one month, the data verification must be undertaken at

monthly intervals. The verification must be completed within three weeks after the

end of each month in which the data were collected.

c) For toll traffic monitoring, the data verification must be undertaken at monthly

intervals. The verification must be completed within four days after the end of each

month in which the data were collected.

In situations where suspect data have been identified and investigations are required to

establish the cause of such data, the Service Provider must inform the Employer

accordingly who, at its discretion, may allow a time extension for the submission of the

verified data.

19.8 Complete data sets

In terms of these specifications, a data set for a specific monitoring period is defined as a

“complete” data set for the period when it does not contain any missing or bad data during

the period. No data may be missing or bad for any of the lanes of a monitoring site, even if

the monitoring system has been subdivided into partial sites. This requirement also applies

where the Employer has specified that data must be submitted for each individual partial

site.

Complete data sets must be provided as follows for all the lanes of a monitoring site:

a) Automatic traffic monitoring. Full data sets must be provided for monitoring

intervals of 24 hours of a day (subject to the grace period specified below). There

may be no data identified as missing or bad over the full day.

b) HS WIM Monitoring. Full data sets must be provided for monitoring intervals of one

hour. There may be no data identified as missing or bad over the hour.



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c) LS WIM Monitoring. Similar to HS WIM Monitoring, except that data sets must only

be provided for vehicles that were monitored.

d) Toll Traffic Monitoring. Full data sets must be provided for monitoring intervals of

one hour. There may be no data identified as missing or bad over the hour.

e) Manual traffic monitoring. Full data sets must be provided for the full specified

monitoring duration. No grace periods are allowed and no data may be identified

as missing or bad over the monitoring period.

For automatic monitoring, no grace periods will be allowed for data collection that is

undertaken in monitoring intervals of one hour. For monitoring intervals of 24 hours of the

day (traffic monitoring), a maximum of two grace periods of 5 minutes will be allowed during

any two of the 24 hours of a day, subject to the requirement that such grace will not be

allowed for more than a maximum of two days when the monitoring duration is shorter than

30 days. For monitoring durations longer than 30 days, a maximum of two days will be

allowed for each calendar month of monitoring. Days will be considered to be completed

even if data are missing or bad during these two 5-minute grace periods, subject to the

maximum allowance of two days.

Time of day Grace period per hour

04:00 to 12:00 5 Min/hour

12:00 to 04:00 10 Min/hour

19.9 Daily count classification

The Service Provider is responsible for classifying daily traffic counts in accordance with

the “day classifications” provided in the South African Standard Traffic Data Collection

Format. Two classifications are required, namely:

a) Normal/Abnormal classification (non-holidays, holidays and influenced days).

b) Traffic pattern classification.

The classification must be undertaken using the data management software, but the

classification must be manually verified and adjusted where necessary.

19.10 Data calibration

The purpose of data calibration is to adjust collected data using calibration factors. The

Service Provider will be responsible for undertaking the data calibration by means of the

data management software. The following calibration must be undertaken:

a) WIM systematic calibration on a monthly basis with the purpose of establishing

monthly calibration factors.

b) WIM load correction calibration on an annual basis with the purpose of correcting

axle load distributions for dynamic loads.

19.11 Data summaries

The Service Provider is responsible for preparing data summaries. These summaries must

be prepared using the data management software.



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For short-term (shorter than one year) monitoring data summaries, the software must be

used to expand the short-term traffic characteristics to equivalent annual characteristics.

Such expanded data are reported as part of the data summaries. For this purpose, the

Service Provider in cooperation with the Employer, must group monitoring sites into traffic

strata and clusters of sites with similar annual traffic patterns in accordance with the

requirements of Chapter 11 (Automatic monitoring site requirements) of these

specifications.

For long-term (one year or longer) monitoring, a data summary must be submitted for each

year of observations. For short-term monitoring, a data summary must be submitted for

each period during which the monitoring was undertaken.

19.12 Data ownership and copyright

The ownership of all collected data vests in the Employer and any copyright or intellectual

property that the Service Provider may have in terms of South African or international law

is transferred to Employer when data are submitted. This data include both the original

logger data, as well as any converted or derived data that may have been made available

by the Service Provider.

The Service Provider shall not divulge, or provide to any organisation or person any of the

data without the prior knowledge and written approval of the Employer. Where allowed by

the Employer, such data may be made available to other organisations or persons and the

Service Provider will be entitled to charge a reasonable fee for the cost involved in the

provision of the data.

Part 6: Service Specification and Payment Requirements


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Part 6

Service Specification and

Payment Requirements



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Part 6: Monitoring Service and Payment Requirements

Part 6 contains the requirements that are applicable to the specification of monitoring

services to be provided and the payment for such services. These requirements are

applicable to the provision of automatic traffic and WIM monitoring services as well as

manual traffic monitoring services. These requirements are provided in the following

chapters:

Chapter 20 Monitoring service specification.

Chapter 21 Payment requirements.



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20 MONITORING SERVICE SPECIFICATION

20.1 Introduction

This chapter specifies the method that must be used for specifying automatic and manual

traffic monitoring services for tender purposes. Tender rates must differentiate between the

different monitoring services on the basis of the requirements specified in this chapter.

20.2 Optional specifications

The Employer may specify the following requirements for a particular project. In the

absence of such specifications, the requirements provided in these specifications will apply:

a) The Certification Organisation that must be used for the certification of Service

Providers and monitoring systems as required in Chapter 2 (Service provider and

monitoring system certification).

b) Whether or not automatic monitoring systems must be removed on completion of

monitoring system as required in Chapter 12 (Installed automatic monitoring

system requirements).

c) Whether or not assessments of the road pavement requirements specified in

Chapter 11 (Automatic monitoring site requirements) and Chapter 12 (Installed

automatic monitoring system requirements) must be undertaken.

d) The data management and authentication software that must be used for the

verification and authentication of data as required in Chapter 19 (Monitoring data

requirements).

e) The country or countries in which the monitoring services must be provided as

required in this chapter.

20.3 Schedule of quantities

The monitoring services that are required by the Employer will be specified by means of a

schedule of quantities. The schedule will list the required monitoring services, as well as

the number (quantity) of the required services.

The quantities set out in the schedule of quantities are estimated quantities and are used

for the comparison of tenders. It must be clearly understood that only the actual quantities

of services provided will be measured for payment, and that the scheduled quantities may

be increased or decreased as provided for in these specifications and in the general

conditions of contract.



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20.4 Pay items for monitoring services

The schedule of quantities will provide for the following pay items for monitoring services:

Pay item Unit

Per monitoring service location, characteristics, type, size and duration:

a) New automatic monitoring sites Number of days/hours

b) Existing automatic monitoring sites Number of days/hours

c) Manual traffic monitoring sites Number of days/hours

The unit of measurement for payment shall be the following:

a) Number of days for traffic monitoring. A day shall consist of the 24 hours from

midnight to midnight of a calendar day and shall include all the days of the week.

Automatic traffic monitoring must be undertaken over all 24 hours of the day while

manual traffic monitoring are required for specific hours of the day.

b) Number of hours for HS and LS WIM and toll monitoring. An hour shall be a full

hour of a day.

The measurements for payment purposes shall only include the following:

a) Where required, only Normal days will be measured (Abnormal days are excluded

even if monitoring was undertaken on such days).

b) Days or hours for which “complete” data sets have been submitted as specified in

Chapter 19 (Monitoring data requirements).

20.5 Pay items for road pavement tests

The schedule of quantities will also provide for pay items for the following road pavement

tests that may be required at monitoring sites:

Pay item Unit

Per monitoring service location:

a) Rutting measurements and tests Per monitoring site

b) International Roughness Index measurements and tests Per monitoring site

c) Deflection measurements and tests Per monitoring site

d) Faulting measurements and tests Per monitoring site

e) Visual assessment of structural defects Per monitoring site

The unit of measurement for payment shall be the number of monitoring sites at which the

different road pavement tests are required.

20.6 Monitoring service locations

The pay items will differentiate between different monitoring service locations. The

locations may be specified either specifically or generally (or both).



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Specific monitoring locations are specific road sections or toll plazas on or at which the

monitoring services must be undertaken. The precise positions of the monitoring sites will,

however, not be given since the Service Provider is responsible for determining the exact

location for the monitoring site, as specified in Chapter 11 (Automatic monitoring site

requirements) of these specifications.

General locations give a general indication of the areas in which sites will be required as

well as the general characteristics of the monitoring sites. One or more of the following area

definitions will be used:

a) The Employer will specify the country or countries in which the monitoring services

will be required, in which case the Employer may select monitoring locations on

any road in the country or countries (irrespective of the authority that has

jurisdiction of the road). In the absence of such specifications, the monitoring

services will be undertaken in the Republic of South Africa.

b) The Employer may also optionally specify provinces, municipalities, regions or sub-

regions in which services will be required. Where specified, the Employer may

select monitoring locations on any road in the province, municipality, region or sub-

region (irrespective of the authority that has jurisdiction of the road).

The Employer will also differentiate between locations with a low or high risk of theft or

vandalism. The Employer will decide on the risk classification applicable to a monitoring

service location.

20.7 Monitoring site characteristics

In situations where monitoring site locations are specified generically, the Employer may

also optionally specify the following monitoring site characteristics:

a) Communications availability. In such cases the Employer may differentiate

between sites on the basis of the availability of communication facilities.

b) Electricity availability. In such cases the Employer may differentiate between sites

on the basis of the availability of electricity.

c) Road types on which monitoring services are required. In such cases, the Employer

may differentiate between road types such as two-lane and multilane roads

(including freeways).

d) Pavement types on which monitoring services are required. In such cases, the

Employer may differentiate between pavement types such as gravel, asphalt and

concrete pavements.

If the above characteristics are not specified, then the monitoring service must be provided

irrespective of the characteristics of the monitoring sites.

20.8 Monitoring service type, size and duration

The pay items will differentiate between monitoring types, sizes and durations as follows:

e) The types of monitoring services.

f) Sizes of the required services (the number of lanes that must be monitored).

g) Durations of the monitoring services.



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The monitoring types and durations will be specified in terms of the requirements specified

in Chapter 18 (Monitoring service requirements).

20.9 New and existing monitoring sites

The pay items will differentiate between new and existing monitoring sites. Where an

existing monitoring site is available on a road section or at a toll plaza, the Service Provider

will be required to re-use such sites unless the site is found unsuitable.

Tender rates must be provided for new and existing monitoring sites. The tender rate for

an existing monitoring site will be used when an existing site can be re-used. The tender

rate for a new site will be used when the existing site cannot be re-used or where a suitable

existing site is not available.

The tender rate for an existing site shall not be higher than the rate for a new site. Tenders

in which such tender rates have been provided will be invalidated and disqualified.



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21 PAYMENT REQUIREMENTS

21.1 Introduction

This chapter provides requirements for the payments of the Service Provider for traffic and

WIM monitoring services delivered in terms of these specifications.

21.2 Contract rates

In computing the final contract amount, payment shall be based on the actual quantity (days

of hours) of authorised work done in accordance with the specifications, irrespective of

whether the actual quantities are more, or less than the scheduled quantities. Where

allowed by the Employer, the Service Provider may either repeat or extend a monitoring

service (as specified in Chapter 18 (Monitoring service requirements)) at the expense of


Where no rate or price has been entered against an item in the schedule of quantities by a

tenderer, even where no quantity is given, it shall be taken that the Service Provider does

not require any compensation for such work and zero payment will be made for the service.

The schedule may include items for which no quantity is given against and item. In such

cases, tender rates must be entered for undertaking the services should such services

become required during the project. Payment for such services will only be made if the

services are specifically provided.

21.3 Rates to be inclusive

The rates submitted in a tender must provide for the full execution and completion of the

traffic monitoring services as specified, including the procurement, provision, supply,

furnishing, placement, installation, maintenance, operation and removal (where required)

of all labour, supervision, plant, tools, equipment, material, transport, loading and off-

loading, handling, wastage, temporary work, testing, assessment, quality control,

overheads, guarantees, risk, insurance, profit and obligations or incidentals required for the

provision of the services. This also includes but is not limited to the following:

a) Certification of Service Providers and monitoring systems, including the

procurement of the services of the Certification Organisation for such certification.

b) Provision of the monitoring systems, equipment, sensors, software, software that

is made available to the Employer, ancillary or auxiliary facilities, materials,

assessments, quality control and assurance, reports and manuals.

c) Site selection, site assessments, assessment tests, site information records,

implementation of the stratification system, wayleave applications, work on

properties outside the road reserve, site establishment, removal, accommodation

of traffic, health and safety obligations and all other work required on site.



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d) Assessments of installed monitoring system and assessment reports.

e) Data collection, extraction, conversion, submission, verification, calibration,

analysis, and preparation of summaries. It also includes the development and

updating of the traffic monitoring programme.

f) The attendance of any required meetings with the Employer.

g) Compliance with all legal and other requirements of these specifications.

21.4 Payments for services

Monitoring services will be paid for as follows:

a) For monitoring shorter than or equal to three months, payment will only be made

when a complete data set has been submitted for the full duration of the service.

b) For monitoring longer than three months, monthly payments will be made for

completed data sets that have been submitted. The first payment will only be made

when complete data sets have been submitted for a period of 30 days or 720 hours.

No payment will be made unless the following information and data have been submitted

to the Employer:

a) Site information records as specified in Chapter 11 (Automatic monitoring site

requirements) of these specifications.

b) The assessment record for the monitoring site by the Service Provider as specified

in Chapter 13 (Installed automatic monitoring system assessments).

c) Data sets submitted as specified in Chapter 19 (Monitoring data requirements).

Payment for monitoring durations of 3 months and shorter and for the last 30 days or 720

hours of monitoring services longer than 3 months will only be made after removal of the

monitoring system (if and where required by the Employer) in accordance with the

requirements of Chapter 12 (Installed automatic monitoring system requirements) of these

specifications. The final payment will only be made when the Employer is satisfied that the

removal complies with the requirements of this chapter.

21.5 Changed monitoring durations

The duration of long-term and toll traffic monitoring services may be changed by the

Employer in accordance with the requirements of Chapter 18 (Monitoring service

requirements). Where the duration has been changed, payment for the changed service

will be made in terms of the pay item and tariff applicable to the changed duration.

Where payments have already been made for a partially completed service, the payments

will be adjusted in accordance with the payments already received by the Service Provider.

The adjustment shall be made as a single-sum addition to or subtraction from the next

payment due to the Service Provider.



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21.6 Discontinuation of monitoring services

In situations where a monitoring service has been discontinued by the Service Provider

before completion of the service, payment will only be made for complete data sets in

accordance with the requirements of this chapter.

However, in situations where the Employer has issued an instruction for the discontinuation

of the monitoring service before completion of the service, the hourly or daily tariff rate for

the services that have already been delivered will be increased in accordance with the

following formula:

RAdjusted =TCompleted + TOutstanding

TCompleted

RTender

In which:

RAdjusted = Adjusted hourly or daily rate

RTender = Tendered hourly or daily rate

TCompleted = Duration of services that were delivered before discontinuation

ROutstanding = Duration of services not delivered due to discontinuation

In situations where the instruction was issued after a monitoring system was installed but

before the service could commence (TCompleted = 0), a value of TCompleted = 1 shall be used to

calculate the adjusted rate and payment due to the Service Provider.

The above adjusted hourly or daily rate shall be applied to the duration TCompleted of services

that were delivered before the service was discontinued. The adjustment shall be made as

a single-sum addition to the next payment due to the Service Provider.

Where a long-term or toll traffic monitoring service is discontinued, the duration of the

service must be reduced to the minimum required to cover the completed service. Payment

for the service will be made in terms of the pay item and tariff applicable to the reduced

duration.

Part 7: Appendices to the Specifications


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Part 7

Appendices to the

Specifications



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Part 7 contains the appendices to the specifications. These appendices are the following:

Appendix A Methodologies for determining tolerance limits and intervals.

Appendix B Definitions of Normal and Abnormal days.

Appendix C Monitoring system accuracy assessment method.

Appendix D Data verification tests.

Appendix E List of references.



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APPENDIX A

TOLERANCE LIMITS AND INTERVALS

A.1 Introduction

The requirements that are provided in the specifications for the accuracy of traffic and WIM

monitoring systems are only applicable when a very large number of observations,

representative of the population are made. In practice, this is not possible and the

assessment of accuracy can only be determined on the basis of a sample containing a

limited number of observations. Statistical methods must be applied to account for the

uncertainty introduced by sampling.

It is important to note that the statistical tests provided in this appendix are used to either

accept or reject traffic or WIM monitoring equipment. When a test results in a rejection, the

System Supplier is allowed to increase the sample size by means of additional

measurements which may result in the acceptance of the equipment. This, however, is

subject to the requirement that no adjustments are made to the equipment and that the

additional measurements are undertaken as if part of the original test.

The statistical procedures that must be applied are provided in the following two sections:

• A.2 Tolerance limits tests for proportions

• A.3 Tolerance intervals for percentages within limits (PWL)

The statistical background to these tests is provided in other sections of this appendix.

A.2 Procedure: Tolerance limit tests for proportions

Tolerance limit tests for proportions are used for testing the number of “failed” or

“erroneous” observations on the basis of a sample. Table A1 is used to determine the

maximum failure count for different tolerance limits and sample sizes. The equipment is

accepted if the failure count obtained by means of a sample is less than or equal to the

maximum count in the table, otherwise it is rejected:

The following is an example of how the table is applied. Suppose that a sample is taken

and the following is found:

• Sample size is 200.

• Number of failures in sample is 13.

• The specified tolerance limit is 10%.

From the table, for a tolerance limit of 10% and a sample size of 200, the maximum

allowable failure count is given as 12. The number of failures obtained from the sample is

13, which exceeds this maximum and the equipment therefore fails the test.

The System Supplier is allowed to increase the sample size if the test is failed. Suppose

the sample size is increased to 300 and the number of failures is now found to be 21.

According to the table the maximum allowable failure count is 21 and the equipment

therefore, passes the test.



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Table A1 is restricted to a limited set of tolerance limits and sample sizes. Additional values

for the allowable failure count may be calculated using the following Microsoft Excel

spreadsheet function (inverse binomial distribution):

x = BINOM.INV(n, p, 0.05) – 1

in which:

x = Maximum allowable failure count

n = Sample size

p = Tolerance limit (as a fraction)

A.3 Procedure: Tolerance Intervals

Tolerance interval tests are used to test the percent-within-limits obtained from a sample.

Table A2 is used for this purpose. This table provides minimum z-values for different

sample sizes. The equipment is accepted if the calculated z-value is equal to or greater

than the minimum z-values. The equipment is otherwise rejected.

The z-value is calculated by means of the following formula:

z =T − Abs(m)

s

in which:

z = Calculated z-value

T = One half the tolerance interval width

m = Sample mean

Abs(m) = Absolute value of mean

s = Standard deviation

The sample mean and standard deviation are determined by means of the following

formulae:

m =∑ Di

n

s = √(Di − m)2

n − 1

In which:

Di = “Deviations” between measured and reference values

n = Sample size

The following is an example of how the table is applied. Suppose that a sample is taken

and the following is found:

• The specified tolerance interval is 15% (half width).

• Sample mean is -3.25%. The sign is removed and the mean is taken as 3.25%.

• Sample standard deviation is 5.00%.

• Sample size is 30.

• The z-value is calculated as (15 – 3.25)/5.00 = 2.25



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From the table, for a tolerance interval of 15% (half width) and a sample size of 30, the

minimum z-value is given as 2.356. The equipment is therefore rejected.

The System Supplier is allowed to increase the sample size if the test is failed. Suppose

the sample size is increased to 50 but it is found that the mean and standard deviation have

not changed (the calculated z-value is still 2.25). From the table, the minimum z-value is

given as 2.246 and the equipment now passes the test.

Table A2 is restricted to a limited set of sample sizes. However, for sample sizes not

covered by the table, the z-values can be linearly interpolated from the table. For sample

sizes of greater than 10 000, a z-value of 1.960 may be used.

A.4 Statistical methodology: General overview

The statistical methodology that is used in the acceptance/rejection tests is based on

standard statistical approaches used in hypothesis testing and quality control. In the

application of hypothesis testing in quality, the null and alternative hypotheses are stated

as follows:

• Ho: The product is of an acceptable quality.

• H1: The product is not of an acceptable quality (and therefore rejected).

In the development of a quality assurance plan, use is made of operating characteristic

(OC) curves which are used to determine the probability of accepting a product as a

function of its true or population quality. These probabilities are also the “client” risk of

making a Type II error where a product is accepted while it has a true quality other than

hypothesised. It is also possible to determine the “producer” risk of a Type I error where a

product is rejected while it in fact has an acceptable quality.

In the development of a quality assurance plan, two levels of quality may be established,

namely the Acceptable and Rejectable quality levels (AQL and RQL). The AQL is the level

which would be preferred by the client, while the RQL is the level at which the product is

considered unacceptable to the client.

The statistical tests provided in this chapter are solely based on the consideration of the

RQL level at which a product is considered unacceptable to the client. The product is

considered acceptable when the quality level is better than the RQL.

In the development of the quality control plans, consideration was only given to the Type II

risk of accepting a product which is considered unacceptable to the client. This level was

fixed at a maximum of 5%. This implies that 1 in 20 unacceptable products will pass the

test.

No consideration was given to the producer risk which can be reduced by increasing the

sample size. Should a product fail a test, the producer will be allowed to repeat the test to

increase the sample size, thus reducing the risk of a Type I error where an acceptable

product fails the test.



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A.5 Statistical methodology: Tolerance limits for proportions

The purpose of the tolerance limit test for proportions is to determine the probability of an

unacceptable proportion of failures or erroneous observations being accepted. This

probability is determined by means of the cumulative Binomial distribution:

FB(x; n; p) = ∑ (ni)

x

i=0

∙ pi ∙ (1 − p)n−i

With:

(ni) =

n!

i! ∙ (n − i)!

In which:

x = Number of failures or erroneous observations in a sample

n = Sample size

p = True or population proportion (tolerance limit)

FB() = Probability of accepting the product

Table A1 provides values of failure counts x for different sample sizes n and tolerance limits

p which would not result in a probability FB(x;n;p) greater than 5%.

A.6 Statistical methodology: Tolerance intervals

The purpose of the tolerance interval test is to determine the probability of accepting a

product with an unacceptable population percent-within-limits (PWL). A population PWL of

95% is prescribed in the specifications for all tolerance interval tests.

A further requirement that is introduced is that not more than 2.5% of the population may

be lower than the lower tolerance limit and not more than 2.5% of the population higher

than the upper tolerance limit. This means that even if the population PWL of 95% is

achieved, a product will fail the test if the 2.5% requirements are not met.

The test is performed by means of a z-value calculated from the sample mean and standard

deviation. In the development of the quality assurance plan, the z-values are actually used

to obtain an estimate of the population PWL. The so-called The Uniformly Minimum

Variance Unbiased Estimator (UMVUE) estimate of this PWL can be obtained by means of

the Student’s t-distribution:

PWL = 0 for z ≤ −n−1

√n

PWL = 1 for z ≥n−1

√n

PWL = FT(t; n − 2) otherwise

In which:

FT() = Cumulative Student’s t-distribution

n = Sample size

t = t-value



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The t-value required in the above formulae is determined as follows:

t = z ∙ √n ∙ (n − 2)

(n − 1)2 + n ∙ z2

The 2.5% requirement means that two tests must actually be applied, namely, a lower as

well as an upper one-side test. These two tests are effectively achieved by using the

absolute value in the formula to determine the z-value (as described previously).

The probability of accepting a product with an unacceptable population PWL was

determined by means of Monte Carlo simulation. In this simulation, samples are repeatedly

taken from a population with a known true PWL. For each sample, the acceptance test (as

described previously) is applied. The number of samples in which the product is accepted

is determined, and the probability of acceptance is determined. This probability must then

be less than the required 5% risk. The simulations are repeated for different minimum z-

values until a z-value is obtained for which the risk is approximately 5%. The minimum z-

values obtained in this manner are provided in Table A2.



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Table A1: Tolerance limits for proportions

Sample Maximum failure count (provided in table) for the following tolerance limits and sample sizes:

size 0.5% 1.0% 2.0% 2.5% 3.0% 3.5% 4.0% 5.0% 6.0% 7.0% 8.0% 9.0% 10.0% 12.0% 15.0% 20.0%

100 N/A N/A N/A N/A 0 0 0 1 1 2 3 4 4 6 8 13

150 N/A N/A 0 0 0 1 1 2 4 5 6 7 8 11 15 21

200 N/A N/A 0 1 1 2 3 4 6 7 9 11 12 16 21 30

250 N/A N/A 1 2 2 3 4 6 8 10 12 14 16 21 27 39

300 N/A 0 1 2 3 5 6 8 11 13 16 18 21 26 34 48

350 N/A 0 2 3 5 6 7 10 13 16 19 22 25 31 41 57

400 N/A 0 3 4 6 7 9 12 15 19 22 26 29 37 47 66

450 N/A 0 3 5 7 9 10 14 18 22 26 30 34 42 54 75

500 -1 1 4 6 8 10 12 16 21 25 29 34 38 47 61 84

600 0 1 6 8 10 13 15 20 26 31 36 42 47 58 75 103

700 0 2 7 10 13 16 19 25 31 37 43 50 56 69 89 122

800 0 3 9 12 15 19 22 29 36 43 51 58 65 80 103 141

900 0 3 10 14 18 22 26 34 42 50 58 66 74 91 117 159

1000 1 4 12 16 20 25 29 38 47 56 65 74 84 102 131 178

1100 1 5 14 18 23 28 33 42 52 62 72 83 93 113 145 197

1200 1 6 15 20 26 31 36 47 58 69 80 91 102 125 159 216

1300 2 6 17 23 28 34 40 51 63 75 87 99 111 136 173 235

1400 2 7 19 25 31 37 43 56 69 82 95 108 121 147 187 255

1500 2 8 20 27 33 40 47 60 74 88 102 116 130 159 201 274

1600 3 9 22 29 36 43 50 65 80 94 109 124 139 170 216 293

1700 3 10 24 31 39 46 54 69 85 101 117 133 149 181 230 312

1800 3 10 26 33 41 49 58 74 91 107 124 141 158 193 244 331

1900 4 11 27 36 44 53 61 79 96 114 132 150 168 204 259 350

2000 4 12 29 38 47 56 65 83 102 120 139 158 177 215 273 370

2200 5 14 32 42 52 62 72 92 113 134 154 175 196 238 302 408

2400 6 15 36 47 58 68 79 102 124 147 169 192 215 261 330 447

2600 6 17 40 51 63 75 87 111 135 160 184 209 234 284 359 486

2800 7 19 43 56 68 81 94 120 147 173 200 226 253 307 388 524

3000 8 20 47 60 74 88 102 130 158 186 215 243 272 330 417 563

3200 9 22 50 65 79 94 109 139 169 200 230 261 291 353 446 602

3400 10 24 54 69 85 101 116 148 180 213 245 278 310 376 475 641

3600 10 25 57 74 90 107 124 158 192 226 260 295 330 399 504 680

3800 11 27 61 78 96 114 131 167 203 239 276 312 349 422 533 719

4000 12 29 65 83 102 120 139 177 215 253 291 329 368 445 562 758

4200 13 31 68 88 107 127 146 186 226 266 306 347 387 469 591 797

4400 14 32 72 92 113 133 154 195 237 279 322 364 406 492 620 836

4600 14 34 76 97 118 140 161 205 249 293 337 381 426 515 649 875

4800 15 36 79 101 124 146 169 214 260 306 352 399 445 538 679 914

5000 16 38 83 106 129 153 176 224 272 320 368 416 464 561 708 953



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Table A2: Tolerance intervals (double one-sided)

Minimum z values for acceptance for different sample sizes

Sample size Minimum z-Value

10 2.833 1100 2.012

20 2.487 1200 2.010

30 2.358 1300 2.008

40 2.289 1400 2.006

50 2.246 1500 2.004

60 2.218 1600 2.003

70 2.196 1700 2.001

80 2.177 1800 2.000

90 2.164 1900 1.999

100 2.150 2000 1.998

120 2.132 2500` 1.995

140 2.117 3000 1.991

160 2.106 3500 1.988

180 2.096 4000 1.987

200 2.089 4500 1.985

250 2.075 5000 1.984

300 2.063 6000 1.982

350 2.055 7000 1.980

400 2.049 8000 1.979

450 2.044 9000 1.978

500 2.038 10000 1.977

550 2.034

600 2.032

650 2.028

700 2.026

750 2.023

800 2.021

850 2.020

900 2.018

950 2.016

1000 2.014



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APPENDIX B

DEFINITION OF NORMAL AND ABNORMAL DAYS

B.1 Introduction

Daily traffic patterns may vary significantly on different days of the year. Differentiation is

made between two basic classes of traffic patterns, namely those counted on Normal and

those counted on Abnormal days. Normal days are days of the year during which traffic

patterns tend to be stable and where these patterns are not affected or influenced by

Abnormal or exceptional events.

Abnormal days are days on which the traffic patterns deviate from Normal days due to

events such as school and public holidays (including influenced days). Although Abnormal,

these days can be predicted from published information on holidays.

Exceptional days are Normal days on which some unpredictable event occurred that

affected the traffic pattern. These include events such as road closures, construction,

accidents and adverse weather conditions.

B.2 Normal and Abnormal day definition

Abnormal days can be identified by means of the definitions provided below. Days that are

not Abnormal can be assumed to be Normal but care should be taken to ensure that

unpredictable events have not occurred which could affect the traffic monitoring.

Abnormal Days are defined as the following days of the year (Papenfus and Van As, 2014):

• Public holidays.

• Days influenced by public holidays, as defined in the table below.

• School holidays in any of the provinces of the country, measured for the full

duration of the holiday (i.e. from the first to the last day of the holiday) and including

the last and first school days before and following the holiday.

• December recess, measured from the last (seven-day) week in November up to

the end of the school holidays in January of the following year in any of the

provinces and including the first school day following the holiday.

Weekday of

Public Holiday

Days influenced by Public Holidays

Wed Thu Fri Sat Sun Mon Tue Wed

Sunday

Monday

Tuesday

Wednesday

Thursday

Friday

Saturday

Public Holiday Influenced Days



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APPENDIX C

MONITORING SYSTEM

ACCURACY ASSESSMENT METHOD

C.1 Introduction

This appendix describes the assessment methodology that must be followed when

assessing the accuracy of a monitoring system. This methodology is aimed at simplifying

the process of data verification required by the Certification Organisation for the certification

of a monitoring system.

The tests described in the chapter are mainly based on video and camera recordings but

other data are also required. Manual assessments are still required but the aim of the

method is to minimise such assessments.

C.2 Certification Organisation

The Certification Organisation will be responsible for verifying that the accuracy

assessments have been undertaken in accordance with the specifications and that the

assessments have not been falsified or fabricated. For this purpose, it is not necessary to

verify all the data collected by the System Supplier, and only a random or specific sample

of data needs to be reviewed and verified.

The Certification Organisation therefore does not have to attend the assessment for the full

duration of the test and will only attend the assessments on a sampling basis. For this

purpose, the System Supplier must make arrangements with the Certification Organisation

regarding the assessment programme and the dates and times on and during which the

tests will be undertaken. The Certification Organisation will attend the tests without prior

notification to the System Supplier.

C.3 Assessment tests

The following assessment tests must be undertaken as part of the assessment

methodology:

a) Video recordings of vehicles travelling over the monitoring system. These video

recordings are used in all the assessments that must be undertaken. Most of the

data required by the assessments will be captured from these videos and it is

therefore important that the video recordings must be of a high quality.



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Two videos must be recorded for the following purposes:

i) One video for the assessment of vehicle detection and classification

accuracies. This video must show the whole vehicle as well as the axles

of the vehicle as it crosses the monitoring site.

These videos must be taken over a continuous period of time and not be

triggered by the presence of vehicles on the monitor site. The videos must

continue even if no vehicles are detected on the site. The continuous

recording is required to determine whether there were any false vehicle

detections by the monitoring equipment and whether there were any

vehicles missed by the equipment.

A system must be used which will allow the determination of the date and

time of each individual frame in the video recordings to at least the nearest

second. This is required to allow later matching of the video recordings

with data collected by the monitoring system.

ii) A second video used for assessments in which registration number

recordings are required, such as assessments of vehicle lengths and WIM

loads. This video must clearly show the registration numbers of the vehicle.

If possible, the quality of the video should provide for optical character

recognition of the registration numbers.

The videos should preferably be triggered by the presence of vehicles on

the monitoring site. For these assessments it is not necessary to make

video recordings when no vehicles are detected on the site.

b) Speed camera recordings of speeds of vehicles travelling over the monitoring site.

The vehicle speed recordings must be made with the same accuracy required for

speed law enforcement. Photographs taken by the camera must show an image of

the vehicle together with the date, time and speed of the vehicle (and optionally the

registration number). It should also be possible to search for a photo with a specific

date and time by means of a computer.

The photographs are required to serve as verification that the speed

measurements have been undertaken while the date/time stamp is required to link

the data to the monitoring system data (the registration number may also be used

for this purpose).

c) Measuring tape and camera recordings of vehicle length and axle spacing. These

measurements should preferably be undertaken at locations where vehicles are

already stopped for another purpose, such as at toll gates or weighbridges. At toll

gates or weighbridges, the authority of the operator must first be obtained before

measurements are undertaken. The measurements taken at weighbridges will only

provide data for heavy vehicles, and additional surveys will be required for light

vehicles. Law enforcement officers must then be used in such additional surveys

to stop vehicles.

Vehicle manufacturer information on vehicle lengths and axle spacing must be

used as far as possible. Tape measurements should only be used when such

information is not available.



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A measuring tape may be used to measure the vehicle length and axle spacing,

but electronic distance measurement equipment may also be used for this purpose.

At least five persons are required for the measurements: one person to inform the

driver and vehicle occupants about the purpose of the measurements and to

exercise control over the vehicle, two persons to hold the tape, a fourth person to

read the distance from the tape and the fifth to record the distance on a form. The

distances must be read cumulatively from the tape.

Cameras must be used to record images of the vehicle together with the

registration number, date and time. It should also be possible to search for a photo

with a specific date and time by means of a computer. The photographs are

required to serve as verification that the vehicle length and axle spacing

measurements have been undertaken while the registration number is required to

link the data to the monitoring system data.

d) Weighbridge (static) load measurements are required for the assessment of HS

and LS WIM monitoring systems. The System Supplier must make arrangements

with the weighbridge operator to obtain the load records from the weighbridge. The

Certification Organisation will also independently obtain the weighbridge load

records for the purpose of verifying the records. The load records must include the

registration numbers of vehicles.

C.4 Accuracy assessments

The accuracy assessments must be undertaken as follows:

a) Videos must be used for the manual assessment of vehicle, trailer, axle, wheel and

dual/tyre detections and for the manual classification of vehicles.

b) Vehicle speeds must be obtained from the speed camera photographs, together

with the date and time (and optionally the registration number). The speeds must

be linked to the vehicle data captured using either the date/time or registration

number recordings. All photographs must be submitted to the Certification

Organisation immediately/shortly after the speed observations. This is to ensure

that no vehicles are excluded from the assessment (an explanation is required

should any vehicles be excluded).

c) The vehicle length and axle spacing data must be manually captured together with

the data/time and registration number obtained from the photographs. The data

must be linked to the vehicle data captured by means of the video recordings using

the dates, times and registration numbers. The original, on site measurements

must be submitted to the Certification Organisation immediately/shortly after the

manual measurements were taken. This is to ensure that no vehicles are excluded

from the assessment (an explanation is required should any vehicles be excluded).

d) The load data required for the assessment of HS and LS WIMs are obtained

directly from the weighbridge load records. This data must be linked to the video

data by means of the dates, times and registration numbers. The weighbridge load

records must be obtained from the weighbridge operators. Where such

weighbridge records are available, all vehicles measured at the weighbridge must

be included in the assessment. An explanation is required for vehicles that are not

included (e.g. triggered the off-scale sensor, travelled in the non-WIM lane, etc.).



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The System Supplier must develop a computerised database in which all the data are

captured, including the data obtained from the monitoring system and the weighbridge. The

database must also provide links to the video recordings and camera images.

C.5 Certification Organisation review

The System Supplier must make a computer system and software available to the

Certification Organisation for the verification of the data. This software must allow for the

viewing of the captured data, as well as the video recordings and camera images.

The Certification Organisation must be able to select a random sample of vehicles to

review. Provision must also be made to select a period of time over which the videos can

be viewed for possible false vehicle detections. Provision must be made in the software

and database to capture the results of the review by the Certification Organisation.

The functionality of the software must provide for the following:

a) The viewing of all captured data that are required for the assessment. This data

should, where possible, be shown in a graphical form (e.g. against a drawing of the

vehicle).

b) The viewing of the video recordings and camera images of the vehicle on a

computer screen. Two or more screens may be required to allow simultaneous

viewing of all the data and images.

c) The software must automatically link recorded data with the video recordings and

camera images. Provision must also be made for the synchronised paging (up and

down) through the data, video recordings and photo images.

d) Provision must also be made for a search facility to search vehicles by means of

the date/time stamps or registration numbers.

Provision must also be made to export the database together with the results of the review

to a spreadsheet. This spreadsheet must also show all the calculations required for the

accuracy assessments, together with the results of the assessments. This spreadsheet

must be made available to the Certification Organisation for review.



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APPENDIX D

DATA VERIFICATION TESTS

D.1 Introduction

The data management software specified by the Employer shall be used for the purposes

of data verification and calibration. An overview of the tests that must be undertaken is

provided in this appendix.

The software provides for three levels of verification tests and the Service Provider will be

required to undertake all three levels of tests. The test levels are as follows:

a) First level tests undertaken on submission of data to the software.

b) Second level tests undertaken on a monthly basis (calendar months) or when the

monitoring duration is shorter than one month.

c) Third level tests are usually undertaken on an annual basis (calendar years) but

may be undertaken over a shorter period when data are not available for a

whole year.

The following general procedure is followed during the three levels of verification tests:

a) Tests are first undertaken to verify that the data comply with the requirements of

the South African Standard Traffic Data Collection Format. Tests will also be

undertaken to authenticate the data. Should any data fail this test, then the whole

file will be rejected and not processed further.

b) Tests are then undertaken with the purpose of identifying “suspect” and “bad” data.

When such data are identified, a report will be created listing the data and made

available. It will be the responsibility of the Service Provider to investigate the data

and to identify possible causes or reasons why the data are suspect and to make

recommendations whether the data should be accepted or rejected. Rejected data

must be marked as “bad” data. Data may also be marked “uncertain” in situations

where the monitoring services have been undertaken at sites that do not comply

with the road geometry and pavement requirements of these specifications.

c) Tests will also be undertaken with the purpose of identifying periods with “missing”

data. These are periods in which no or partial sets of data have been collected.

D.2 First level tests

First level tests are undertaken on submission of data to the software. The following tests

are required:

a) Data format tests. These tests are undertaken to determine whether data have

been provided correctly according to the requirements of the South African

Standard Traffic Data Collection Format. These tests include inter alia the

following:

i) Tests that individual data items comply with the specified format.



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ii) Tests that data items are within the minimum and maximum ranges

specified in the format.

iii) Tests that data separators (e.g. commas) comply with the format.

iv) Tests for whether header data have been provided and whether this data

are correct.

Data that do not comply with the format requirements will be rejected and not

processed further.

b) Lower and upper bound tests. These tests are undertaken to determine whether

individual vehicle data falls outside lower and upper bounds. Vehicles that fail these

tests are marked as suspect. The tests are undertaken on data items such as

the following:

i) Total vehicle length. This is the measurement from the front to rear

bumpers of the vehicle, including any trailers.

ii) Number of trailers. This is the number of trailers counted per individual

vehicle.

iii) Number of axles. This is the total number of axles counted per individual

vehicle.

iv) Number of steering axles. An axle on a vehicle is considered to be a

steering axle when the first group of axles are spaced less than 1.6 m

apart.

v) Axle spacing. The axle spacing test is applied per axle. A vehicle fails a

test if any of the axle spacing measurements exceed the thresholds.

vi) Average axle load (per axle). The average axle load is the total load of the

vehicle divided by the number of axles.

vii) Individual axle load. This test is applied per individual axle. A vehicle fails

the test if any of the axle loads exceed the thresholds.

viii) Axle load/average load ratios. These ratios are determined as the

individual axle load divided by the average axle load of a vehicle.

D.3 Second level tests

Second level tests are undertaken on a monthly basis, or when a full data set has been

provided for a monitoring duration shorter than one month. The following tests are

undertaken:

a) Traffic pattern tests. These tests are undertaken per traffic stream using hourly

traffic counts for the 24 hours of the day. A pattern matching algorithm is used for

these tests and will group the patterns in similar clusters. The tests are used for

the identification of suspect or missing data as well as for the classification of the

data as Normal, Abnormal, etc. The software will undertake the classification, but

each classification must be confirmed manually.

b) Daily traffic count tests. These tests are undertaken per traffic stream using total

24-hour counts. The counts are compared with previous counts and any outliers

will be marked as suspect for further investigation.

c) Monthly failure rate tests. Tests are undertaken of the percentage of vehicles that

fail the lower and upper bound tests previously described. Should these

percentages exceed the maximum allowable percentages, then the data are



- 127 -

marked as suspect for the whole month. The tests are undertaken separately for

each lane of traffic.

The minimum sample size for the test is 500 vehicles. Where necessary, vehicles

from a previous month(s) will be added to the sample to ensure this sample size.

d) Systematic calibration tests. These tests are performed as part of the systematic

calibration of axle loads. The tests are only applied to trucks selected to form part

of the calibration. The tests are undertaken separately for each load sensor. The

following tests are undertaken:

i) Allowable range for the calibration factors.

ii) Maximum standard deviation for the total tractor load.

iii) Allowable range for average front axle load.

iv) Maximum standard deviation for the front axle load.

v) Average axle spacing between 2nd and 3rd axles.

vi) Standard deviation of axle spacing between 2nd and 3rd axles.

e) Recalibration tests. These tests are applied on a monthly basis to determine

whether any changes may have occurred that may affect the system calibration.

The tests are undertaken separately for each load sensor.

D.4 Third level tests

Third level tests are undertaken on an annual basis (calendar years) but may be undertaken

over a shorter period when data are not available for a whole year. The purpose of the tests

is to determine whether possible changes have occurred over the long term. The tests are

undertaken for each traffic stream at a monitoring site.

Use is made of daily or monthly averages which are plotted over time to establish whether

there are any unexpected changes or trends in the observations. Observations are usually

required over a period of several months before it would be possible to identify such

changes or trends.

The following characteristics are included in the tests:

a) Traffic count tests (daily and monthly). The traffic count tests are undertaken for

daily traffic counts, as well as the average daily count for the month.

b) Percentage composition (monthly). The percentage composition test is used to

check the consistency of the percentage of heavy vehicles classified as short,

medium and long.

c) Systematic calibration factor (monthly). This factor should normally remain

constant over time, but it could be affected by the recalibration of equipment in the

field. It is also possible for the calibration of the equipment to “drift” over time. Any

unexpected changes in the calibration factor should be investigated to establish

the reasons for such changes.

d) Average front axle load (monthly). The average front axle load consistency check

uses the average observed load of the front axle of the 6- and 7-axle trucks used

in the calibration method, but without the application of the average axle load

criterion of 6.5 to 8.5 tons. The front axle loads are adjusted using the calibration

factor.



- 128 -

e) Standard deviation in front axle load (monthly). The front axle load standard

deviation consistency check uses the same trucks and axles as for the average

front axle load test.

f) Average number of axles per vehicle (monthly). The averages are determined for

heavy vehicles classified as short, medium and long.

g) Average number of E80’s per axle (monthly). The tests are undertaken for each of

the short, medium and long heavy vehicle classes.

h) Average vehicle length (monthly). The tests are undertaken for the short, medium

and long heavy vehicle classes.

i) Percentage unclassified vehicles (monthly). Unclassified vehicles are those that

could not be classified by the equipment.



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APPENDIX E

LIST OF REFENCES

AASHTO, 2006, Roadside Design Guide, 3rd Edition, Washington DC

ASTM, 2002, Standard specification for Highway Weigh-In-Motion (WIM) Systems with

User Requirements and Test Methods, Specification number E 1381-02, United States.

COST 323, 1999, Weigh-in-Motion of Road Vehicles. Final Report, Appendix I, European

WIM Specifications, Version 3.0.

COTO, 2011, South African Standard Traffic Data Collection Format, TMH14 (Latest

available version), Pretoria.

COTO, 2013, Pavement Surveillance Measurements TMH13 (Latest available

version), Pretoria.

COTO, 2013, Visual Assessment Manual for Roads TMH9 (Latest available

version), Pretoria.

COTO, 2015, TMH 8, Traffic and Axle Load Monitoring Procedures, Pretoria.

COLTO, 1998, The Standard Specifications for Road and Bridge Works for State Road

Authorities of the Land Transport Officials.

Department of Transport, SADC and South African Road Traffic Signs Manual (Volumes 1

to 4).

De Wet, D P G. 2008, Correction of systematic error in WIM data. Draft contract report

SAPDM/A-2/2008/001. SANRAL, Pretoria.

Papenfus AJ and Van As SC, 2014, Traffic Stratification System and Expansion Factors,

Traffic volume and axle load information system, Revision of the South African Pavement

Design Method, South African National Roads Agency Ltd (SANRAL), Pretoria.

Van As, S.C., 2010, Traffic Data Verification and Replacement, Draft contract report

SAPDMA/A-2/2009/03, SANRAL, Pretoria.

Van As, S.C., 2011, WIM Load correction, Draft contract report SAPDMA/A-2/2009/04,

SANRAL, Pretoria.

Documents

Mikros Systems [Home]€¦ · Author: Christo van As Created Date: 1/27/2016 12:23:28 PM